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A N E LEMENTART TEXT - BOOK 




MAY'S 

AN ATOM Y 

PHYSIOLOGY 

AND 

HYGIENE 



LIBRARY OF CONGRESS. 



UNITED STATES OF AMERICA. 



\ 



N 






ANATOMY 



PHYSIOLOGY AND HYGIENE 



WITH SPECIAL REFERENCE TO THE EFFECTS 
OF STIMULANTS AND NARCOTICS 



FOK USE IN PKIMABY AND INTERMEDIATE SCHOOLS 



CHARLES H. MAY, M.D. 

Visiting Oculist and Aurist to the Randall's Island Hospitals, K Y.; Instructor in 

Ophthalmology, Vanderoilt Clinic, College of Physicians and Surgeons, 

N. Y; Ass't Surgeon, N. Y. Ophthalmia and Aural Institute; 

Fellow of the N. Y. Academy of Medicine, etc., etc. 









O^ 




NEW YOEK 
WILLIAM WOOD AND COMPANY 

1890 



Copyright, 1889, by 
WILLIAM WOOD & CO. 



TROWS 

PRINTING AND BOOKBINDING COMPANY, 

NEW rORK. 



PREFACE. 



In the following pages the author has endeavored to pre- 
sent the most important facts relating to the anatomy, phys- 
iology, and hygiene of the human body, in as simple and clear 
a manner possible without undesirable omissions. 

Of late years, physicians have laid great stress upon the 
study of the prevention of disease ; and, keeping pace with 
this improvement, the laity have become better informed about 
matters pertaining to the care of the body than formerly. 
The great utility of such knowledge has led to the enactment 
of laws in New York and other States making provision for 
the study of physiology and hygiene in the public schools, 
with special reference to the effects of stimulants and narcotics 
upon the human system. Such legislative provisions are very 
gratifying ; proper instruction to children on these subjects 
must do much to diminish the amount of sickness and raise 
the general standard of health. 

The author has endeavored to use the simplest terms com- 
patible with clearness. A certain number of technical terms 
are unavoidable ; these are denned in the glossary at the end 
of the volume. 

The lessons will be made more interesting and valuable if 
illustrated by the various tissues obtainable at the butchers' ; 



4 PREFACE. 

thus the heart of a calf will serve nicely to show the general 
shape and arrangement of cavities and valves in the human 
heart. In the same way other organs and tissues should be 
utilized by the teacher to elucidate the account of various parts 
of the body. The skeleton and its different parts should be 
before the class in reciting upon the bones. 

In the description of the effects of stimulants and narcotics 
upon the human body, only such statements have been made 
as can be found in the works of standard authors on these 
subjects ; it is not necessary to deviate from the truth, in order 
to impress children with the great amount of bodily harm and 
misery, which the extensive indulgence in stimulants and nar- 
cotics causes. 

The synopsis given at the end of each chapter is intended to 
be of use in reviews and in guiding the teacher in a systematic 
presentation of the subject. 

CHARLES H. MAY, M.D. 
Hoffman Arms, 
Madison Avenue and 59th Street, 

New York City, September 15, 1889. 



CONTENTS. 



CHAPTEK I. 

Introduction. 



The Human Body the Highest Form of Living Being — What Hygiene 
Treats of — What Anatomy Teaches Us — What we Learn by the Study 
of Physiology — Differences in Meaning of Terms Anatomy, Physiol- 
ogy, and Hygiene — Different Forms of Animal Life — Life in Plants 
— Differences between Plants and Animals — Organs — Functions — 
Subdivisions of the Body — Tissues — Further Subdivisions, the Cell, 
the Fibre— Parts of the Body— The Head and Neck— The Trunk— 
The Upper Limbs — The Fingers— The Lower Limbs — Synopsis of 
Introduction — Questions on Introduction 13 

CHAPTER n. 

The Framework or Skeleton. 

Position in the Higher Animals— Uses of Bones : Support, Protection, 
Strength, Motion — Number of Bones — Forms of Bones : Long, Short, 
Flat, Irregular — Structure of Bone : Surface, Interior, Periosteum, 
Spaces, Color — Composition of Bone — Variations in Composition in 
Early and in Advanced Life — Care of the Skeleton : Effects of Faulty 
Position, Tight Clothing, Improperly-shaped Shoes, Stimulants and 
Narcotics, Poor Health — Fracture of a Bone — Parts of the Skeleton : 
Head, Trunk, Upper and Lower Limbs— Bones of the Head : Cranium 
and Face — The Cranium : Frontal, Parietal, Occipital, Temporal, etc. ; 
Ragged Edges — The Face : Orbits ; Nose ; Nasal and Malar Bones ; 
Upper and Lower Jaws — Mobility of the Skull— Bones of the Trunk 
— The Spinal Column ; Sacrum and Coccyx ; Canal for Spinal Cord 
—The Pelvis — The Hip-Bone — The Collar-Bone — The Shoulder- 



b CONTENTS. 

Blade— The Breast-Bone— The Ribs: True, False, Floating — The 
Chest : Boundaries ; the Diaphragm — The Bones of Upper Limb — 
The Humerus — The Bones of the Forearm; Radius, Ulna — The 
Bones of the Wrist and Hand : the Wrist, the Palm, the Fingers— 
The Bones of the Lower Limb— The Femur — The Patella— The 
Bones of the Leg : Tibia," Fibula— The Bones of the Foot : the Heel, 
Instep, Toes — Synopsis of Skeleton — Questions on the Skeleton. 21 

CHAPTER III. 

The Joints. 

Definition — Uses — Subdivision — Immovable Joints — Sutures — Slightly- 
Movable Joints : General Arrangement, Ligaments, Varieties : Glid- 
ing, Hinge, Pivot, Ball-and-Socket — Accidents to Joints — Synopsis 
of Joints — Questions on the Joints 41 



CHAPTER IV. 

The Muscles and Motion. 

Function of Muscles — Description of Muscle-tissue — Tendons — Fat — 
Uses of Fat : Warmth, Protection, Food, Appearance — Kinds of 
Muscle-tissue — Voluntary Muscles — Involuntary Muscles — Mixed 
Muscles — How Muscles Act — Influence of the Brain and Nerves — 
Ordinary Muscular Movements very Complex — Groups of Muscles — 
Facial Expressions— Number of Muscles— Shape of Muscles— Size of 
Muscles— A Few Important Muscles : Biceps, Triceps, Pectoralis, 
Diaphragm— Tendon of Achilles— The Care of Muscles— Exercise : 
Necessity, Amount, Kind, Proper and Improper — Effects of Alcohol 
and Tobacco on Muscles— Changes in Muscle by Use of Alcohol- 
Synopsis of Muscles and Motion— Questions on Muscles and Mo- 
tion 46 



CHAPTER V. 

Food and Drink. 

Necessity for Food and Drink — Essential to Life— Difference in Food of 
Plants and of Animals — Difference in the Food of Different Animals 
— Carnivorous Animals — Herbivorous Animals— Different Kinds of 



CONTENTS. 7- 

Food Required by Man— Fleshy Food— Vegetable Food— Starch- 
Green Vegetables— Fat and Fatty Food— Water— Tea and Coffee- 
Necessity for Combination of all Forms of Food and Water— Some of 
the Simplest Forms of Food— Meat and Fish — Bread— Milk : Cream, 
Butter, Cheese— Eggs— Variety in Food— Proper Food— Methods of 
Cooking: Boiling, Stewing, Frying, Broiling, Roasting, Baking- 
Cautions Regarding Eating — Drinking-water — Dangers of Well- 
water — How Poisoning Occurs — How Avoided — Alcoholic Drinks — 
Properties of Alcohol — How Alcohol is Made — Varieties of Alcoholic 
Drinks — Beers and Ales — Wines — Liquors — Effects of Alcohol and 
Alcoholic Drinks — Influence on Crime — Tendency for the Habit — 
Interference with Digestion — Effects on Stomach, Intestines, Mus- 
cles, Heart, Liver, Blood-vessels, Bodily Warmth, Brain and Nerves 
— Moral Objections to Alcoholic Drinks— Synopsis of Food and Drink 
— Questions on Food and Drink 63 



CHAPTEE VI. 

Digestion. 

Definition — The Various Organs of Digestion —Alimentary Canal — The 
Mouth — Teeth : Temporary, Permanent — Parts of Teeth — Structure 
of Teeth— Names of Teeth— Care of the Teeth— The Salivary Glands : 
Parotid, Sublingual, Submaxillary — Saliva — Effects of Chewing Gum 
—The Throat— The Tongue— The Gullet— The Stomach: Descrip- 
tion, Pylorus, Coats — Gastric Juice---Gastric Tubules — Pepsin— Func- 
tion of Gastric Juice — Uses of Stomach : Digestion, Storehouse, Pul- 
verizer — Stomachs in Certain Lower Animals — Effect of Tobacco on 
Stomach — Effect of Alcohol on Stomach — Discovery of How the 
Stomach Acts— " Heavy" and "Light" Food— The Bowels: Subdi- 
visions, Pylorus, Duodenum, Small Intestine, Large Intestine, At- 
tachment to Backbone, Coats — The Peritoneum — Motion of Intestines 
—Projections on Inner Surface of Intestines— The Work of the In- 
testines : Digestion — Starchy, Fatty, Fleshy Food — Openings into 
Small Intestines : From Pancreas, From Liver — The Liver and Gall- 
bladder : Position, Description — Uses of the Liver : Bile, Purify 
Blood, Remove Impurities— Liver Cells — Bile — Action of Bile — Puri- 
fication of Blood by Liver — The Liver as a Storehouse for Nourish- 
ment—The Unhealthy Liver : Gout— The Drunkard's Liver— The 
Pancreas : Pancreatic Juice — Uses of Pancreatic Juice — Absorption — 



CONTENTS. 

Method of Absorption by Blood-vessels— Lacteals— Habits which are 
Injurious to Proper Digestion— Eating too Quickly, Eating too Much, 
Eating too Many Sweets and Sours, Chewing Gum, Ice-water in Large 
Quantity, Violent Exercise after Meals, Severe Brain- work after 
Meals, Bathing after Meals, Excitement, Alcoholic Drink, Smoking 
—The Spleen: Description, Position, Use, Enlargement— Synopsis 
of Digestion— Questions on Digestion 79 



CHAPTER VII. 

The Blood and the Circulation— The Heart and the Blood- 
vessels. 

Importance of the Blood— Appearance of the Blood, Color— Composition 
of the Blood: Fluid, Globules— Blood-globules : Number— Micro- 
scope— Bed Blood-globules— White Blood-globules— The Plasma— 
The Blood of Other Animals— Use of the Red Blood-globules— Use 
of the Plasma— Difference between the Blood in Arteries and the 
Blood in Veins— Clotting of the Blood— Value of the Clotting of 
Blood — The Circulation : How Seen in the Frog— The Heart— Situa- 
tion of the Heart — Form of the Heart — The Pericardium— Cavities 
of the Heart : Grooves, Auricles, Ventricles — Function of the Heart 
— Frequency of the Heart-beats — Course of the Blood — Circulation 
through the Lungs — Changes in the Blood while Passing through the 
Lungs and through the System : The Aorta — Valves of the Heart — 
The Blood-vessels : Arteries, Veins, Capillaries — The Arteries — The 
Pulse — The Capillaries— The Veins : Differences between Veins and 
Arteries— Valves of the Veins — Rapidity of the Circulation of the 
Blood — Fainting : Its Treatment — Bleeding : Its Treatment, Hemor- 
rhage — How to Have a Good Circulation — Exercise — Effects of Alco- 
hol upon the Heart and the Circulation — Effect of Alcohol upon the 
Arteries, Apoplexy — Effects of Tobacco upon the Heart and Circula- 
tion, " Tobacco Heart "—The Lymphatics, Difference between them 
and Arteries, Use, Course; Lacteals— Synopsis of the Blood and 
the Circulation, the Heart and the Blood-vessels — Questions on 
Chapter VII 104 



CONTENTS. 9 

CHAPTEE VIII. 

The Organs of Voice and Breathing. 

Definitions — Course of the Inspired Air — The Organ of Voice — The Lar- 
ynx—Form and Situation — Parts of Larynx — Triangular and Circular 
Pieces — The Epiglottis — The Vocal Cords — Their Protection of the 
Windpipe — The Vocal Cords in Breathing — How Sounds are Pro- 
duced — The Varieties of Vocal Sounds — Speaking— The Trachea or 
Windpipe — Situation and Form — The Air-passage and the Food-pas- 
sage— Rings of the Windpipe — Branching of the Windpipe — The 
Bronchi — The Lungs — Division and Situation — Shape of the Lungs 
— Structure of the Lungs — Subdivision of the Bronchi — The Air- 
vesicles — The Pleura— Breathing is Involuntary — Movements of the 
Chest in Breathing— Mouth-breathing — Frequency of Breathing — 
Changes which Breathing Produces in the Blood and Tissues — 
Changes Produced in the Air by Breathing — The Poisonous Gases — 
Effects of Impure Air — Purification of the Air— How Plants Live 
and Grow— Ventilation — Simple Means of Ventilating — Absence of 
Draughts— Necessity for Sunlight — Effect of Tight Clothing upon 
Breathing — The Deformed Chest —Effects of Tobacco Smoke upon the 
Lungs and Throat — Synopsis of Organs of Voice and Respiration — 
Questions on Organs of Voice and Respiration 130 



CHAPTER IX. 

The Heat op the Body. 

Our Body may be Compared to a Stove — Fuel — Combustion — Work, the 
Result of the Combustion of Fuel — Refuse, another Result of the 
Burning of Fuel — The Results of the Combustion of Food — Casting 
off the Refuse Materials from the Body— Food and Oxygen Produce 
Heat and Work — Warm-blooded and Cold-blooded Animals— Heat of 
the Human Body in Health — Heat of the Human Body at the Sur- 
face — Heat of the Body in Sickness — Regulation of the Bodily Heat 
—Warm Clothing— How to Keep Warm in Winter— How to Keep Cool 
in Summer — How the Body is Kept Cool in Summer— Effects of the 
Passage of Moisture into the Air — Perspiration — Ice Water in Sum- 
mer—Sunstroke—Effects of Cold— Synopsis of the Heat of the Body 
— Questions on the Heat of the Body ; 148 



10 CONTENTS. 

CHAPTEK X. 

The Nervous System. 

Parts of the System already Described — Functions Existing in both Ani- 
mals and Plants— Similarity in the Structure of Plants and Animals 
— Absence of Nervous System in Plants — Most Perfect Nervous Sys- 
tem in Man — Function of the Nervous System — Subdivisions of the 
Nervous System — Brain — Spinal Cord — Nerves — Examples of the 
Action of the Nervous System— Rapidity of Action of the Nervous 
System —Coverings of the Brain — Size and Weight of the Brain — 
Divisions of the Brain — Cerebrum, Cerebellum, Medulla — The Cere- 
brum — Gray and White Parts of the Cerebrum — The Cerebellum — 
The Medulla — The Cranial Nerves— The Twelve Sets— Functions of 
the Brain — Mind, Will, Thought, Memory, Intelligence — The Work of 
the Brain — Reason and Judgment— Intelligence— Training the Brain 
— The Spinal Cord— Interior of the Spinal Cord — The Spinal Nerves 
— Kinds of Nerves : Sensation and Motion — Functions of the Spinal 
Cord — Reflex Action — Examples of Reflex Action — Sleep — Amount of 
Sleep— Sleep of Children — Uses of Sleep— Time for Sleep— Nervous- 
ness— Wakefulness — Narcotics — Chloral — Chloral Habit — Opium — 
Morphine — Opium and Morphine Habit — Effects of the Opium Habit 
— Cocaine —Cocaine Habit — Effects of Alcohol upon the Nervous Sys- 
tem — Delirium Tremens— Effects of Tobacco upon the Nervous System 
— Effects of Coffee and Tea upon the Nervous System — The Sympa- 
thetic System of Nerves — Synopsis of the Nervous System — Questions 
on the Nervous System 159 



CHAPTER XL 

The Senses. 

Definition — Enumeration — Special Senses — 

The Sense of Touch and the Skin — Thickness — Uses of Skin — Protection — 
The Skin as the Organ of Sensation— Throwing off Water, Salts, and 
Poisonous Matters — Regulating the Bodily Warmth— Structure of 
the Skin— Scarf-skin— True Skin— Color of the Skin— Markings of 
Skin — Attachments of Skin — The Perspiration-tubes— The Pores- 
Perspiration — Sensible and Insensible Perspiration — Uses of the Per- 



CONTENTS. 11 

spiration — The Oil-tubes — The Hair — The Nails— Care of the Skin — 
The Results of Uncleanliness and Filth — Bathing — Warm Baths — 
Cold Baths — Turkish and Russian Baths — Clothing — Exercise — Cos- 
metics — Care of the Hair — Care of the Nails — Synopsis of Sense of 
Touch and the Skin — Questions on the Sense of Touch and the 
Skin 184 

The Nose and the Sense of Smell — Functions of Nose — Breathing Channel 

. and Smelling Channel — Parts of the Nose — Nerves of Smell — Sense 

of Smell in Lower Animals — Cold in the Head — Use of Smell — Sweet 

Scents — Synopsis of Nose and Sense of Smell — Questions on Nose 

and Sense of Smell , . . 195 

The Tongue and the Sense of Taste — Structure of Tongue — Uses of Tongue 
— Uses of Sense of Taste — Abuse of Sense of Taste — Synopsis of 
Tongue and Sense of Taste — Questions on Tongue and Sense of 
Taste 199 

The Eye and the Sense of Sight — Protections to the Eye— The Eyelids— The 
Eyebrows and Eyelashes — Parts of the Eye — Interior of the Eye — 
The Iris — The Muscles of the Eye — How we See — Resemblance of 
the Eye to the Photographer's Camera — The Nerves of the Eye — 
Blindness — Images — The Tears — Care of the Eyes — Rest for the Eyes 
— Fine Print— Direction of the Light— Reading while Lying Down — 
Reading in the Cars — Contagious Eye Disease — Stooping in Reading 
—Weak Sight — Old Sight — Synopsis of Eye and Sense of Sight — 
Questions on the Eye and Sense of Sight 201 

The Ear and the Sense of Hearing — Parts of the Ear — The Outer Ear — 
The Middle Ear— The Bones of the Ear— The Eustachian Tube— The 
Internal Ear — The Nerve of Hearing — Sound — How we Hear — Deaf- 
Mutes — Care of the Ear — Synopsis of the Ear and the Sense of Hear- 
ing — Questions on the Ear and the Sense of Hearing 211 

Glossary 217 

Index , 231 



CHAPTER I. 
INTEODUCTION. 

1. The human body is the highest form of living being; 
consequently, greater care is required to keep it in health 
and to ward off disease than is the case with the lower ani- 
mals. 

2. Hygiene. — The study of how to take care of the body 
and how to prevent disease is called Hygiene. It is a very im- 
portant subject. "An ounce of prevention is worth a pound 
of cure " is an old saying, and is certainly a true one. If we 
wish to avoid sickness we must keep our bodies healthy. In 
order to know how to do this, we must learn about the things 
around us which are harmful and poisonous, so as to avoid 
them ; we must become acquainted with what is good and what 
is improper in our food, what are bad habits to be avoided, 
and also the injurious effects of drink containing alcohol, and 
of tobacco and narcotics. All these things are taught us by the 
study of Hygiene. 

3. But if we are to remember them, we must understand 
how and why it is that certain things and habits are injurious ; 
and to do this intelligently, we must know something about 
the structure of our bodies, and the manner in which they per- 
form their work — that of living. 

4. Anatomy. — The study of the form and structure of the 
different parts of the body is called Anatomy. 

5. Physiology. — The study of how we live is called Phys- 
iology. It explains how we digest our food, how our blood 
circulates, how we breathe, grow, and move, and perform the 



14 ANATOMY, PHYSIOLOGY, AND HYGIENE. 

many actions — some simple, some very difficult — which are 
necessary to life. It is a very interesting subject. 

6. These three branches — anatomy, physiology, and hy- 
giene — naturally go together. To explain their differences, let 
us take an easy example : Suppose a man wishes to be an en- 
gineer upon a locomotive. To perform his duties well there 
are many things connected with the locomotive which he must 
understand. In the first place, he must have a knowledge of 
the different parts of which it is built — this would correspond 
to the study of anatomy in the human being. Again, he must 
understand how the locomotive works — what causes the wheels 
to move, how steam is produced, and how to regulate the 
speed — this we would liken to the study of physiology in the 
human being. Finally, such an engineer must be acquainted 
with the proper care of his locomotive — what fuel to use, how 
to keep it clean, and other things to prevent it from getting 
out of order ; similar knowledge applied to the human body, 
hygiene gives us. 

7. We have been making use of the words life and liv- 
ing beings ; it is well to understand exactly what is meant by 
these : There are a great many different forms of life. The 
human being represents the highest form, while some very 
small animals, that cannot be seen except with the microscope, 
belong to the very lowest classes. Both are examples of ani- 
mal life. In ordinary drinking-water we can see certain of the 
lowest forms of life if we look through a drop of such water 
that has stood for some time ; these animals are so small that 
they must be magnified hundreds of times before we can see 
them ; they are perfectly innocent, and do no harm when we 
drink them. 

8. There is also life in plants ; but it is different from that 
in animals. Plants grow, and they also breathe ; a few of 
them have the power of moving some of their parts, as in the 
case of the Venus Fly-trap. This plant grows in North Carolina ; 
each of its leaves has a part at the top which opens and shuts 



INTRODUCTION. 15 

just like a steel-trap. These trap-like ends of the leaves are 
usually open when the sun shines, and whenever a fly alights 
upon one of them and brushes against the bristles that grow 
from their edges, the trap suddenly closes, capturing the insect 
and usually soon depriving it of life. 

9. Differences between Plants and Animals. — The 
main differences between plants and animals are : 

(1.) Plants exist upon water, gases, and mineral matters 
found in the earth ; this would not be enough to support 
life in animals. 

(2.) Plants consist of different materials from those 
forming animals. 

(3.) Plants have no organs of digestion, such as animals 
have in nearly every instance. 

10. Organ. — The word organ, applied to the human body, 
means a part which performs some special work. For instance, 
the stomach is one of the organs of digestion, because it helps 
to prepare the food so that the blood can be nourished by it ; 
the eye is the organ of sight ; the tongue is the organ of 
taste. 

11. Function. — The special work which any organ of the 
body does is called its function. Thus, it is the function of the 
ear to hear, of the heart to propel the blood through the blood- 
vessels. 

SUBDIVISIONS OP THE BODY. 

12. We may divide the body in many different ways : 

(1.) Into different parts of the body ; such as the head, 
the trunk, the limbs. These again may be subdivided. 

(2.) We may further divide these into the different tis- 
sues. A tissue is one of the simple forms of material of 
which the different parts of the body are composed ; thus, 
the finger consists of bone, fat, muscle, arteries, veins, 
nerves, skin— all these are tissues. 

(3.) If we subdivide still further, and again and again, 



16 ANATOMY, PHYSIOLOGY, AND HYGIENE. 

until we come to the very smallest part, we have the cell, 
the fibre, and a substance between these, which may be jelly- 
like or may be hard. The entire body is formed of mil- 
lions of these cells and fibres and this substance between 
them. They are all very small and we must use a strong 
microscope to see them. It is only when millions of them 
are gathered together that they form a mass large enough 
for us to see with the unaided eye. The cells are of dif- 
ferent shapes, but usually they are more or less rounded. 
The fibres are thread-like. 




Fig. 1.— Some Different Forms of Cells. Fig. 2.— A Collection of Fibres, Separated. 



PARTS OF THE BODY. 

13. The human body can be divided into : 

(1.) The head and neck. 
(2.) The trunk. 
(3.) The limbs. 

14. The Head and Neck.— The head has a large cavity 
for the brain, and smaller ones to receive the eyes, ears, nose, 
and tongue. It is divided into the crown (the top part), and 
the face. 



INTRODUCTION. 



17 





^tKT 


Scalp. 




W^^^ 


. Forehead. 


Cheek . 

Chin ... 


f^fl 


Bridge of Nose. 

Neck. 



Chest 




Heel 

Sole 



Ankle, 
irch or Instep of Foot. 



Fig. 3.— The Names of the Different Parts of the Body. 

2 



18 ANATOMY, PHYSIOLOGY, AND HYGIENE. 

15. The Trunk is that part of the body between the neck 
above, the upper limbs above and on each side, and the lower 
limbs below. It has two large cavities: an upper one, called 
the chest or thorax, for the heart and lungs ; and a lower one, 
called the abdomen, for the organs of digestion. 

16. The Limbs are attached to the trunk. 

The upper I i m b s star t from the should er s. There are two ; 
each consists of an arm, a forearm, and a hand. Where the 
upper limb joins the trunk we have the shoulder and the arm- 
pit. Where the arm and forearm meet we have the elbow. 
Where the forearm and hand meet is the wrist. The front of the 
hand is called the j^alm, the opposite side the back of the hand. 
The fingers are named as follows : 

First— Thumb. 

Second — Index finger. 

Third— Middle finger. 

Fourth — Ring finger. 

Fifth— Little finger. 
The lower limbs start from the hip; each consists of a 
thigh, a leg, and a foot. Where the lower limb joins the trunk 
we have the hip and the groin. Where the thigh and leg meet 
we have the knee. Where the leg and foot meet we have the 
ankle. The under surface of the foot is called the sole, the 
upper surface the arch of the foot, or instep. 



SYNOPSIS. 

Hygiene — Care of body and prevention of disease. 
Anatomy — Form and structure of parts of body. 
Physiology — How we live. 
Life — 1. Animals. 

2. Plants. 
Differences between plants and animals : 

1. Plants exist upon water, gases, and mineral matters 
only. 



INTRODUCTION. 19 

2. Plants consist of different materials from those forming 
animals. 

3. Plants have no organs of digestion. 
Organ — A part "which performs some special work. 
Function — The special work which an organ does. 
Subdivisions of the body : 

a. Structure — Tissues, simple forms of material : 

1. Cell. 2. Fibre. 3. Substance between. 

b. Parts : 

1. Head and neck. 3. Upper limb. 

a. Crown. a. Arm. 

b. Face. b. Forearm. 

c. Hand. 

2. Trunk. 4. Lower limb. 

a. Thorax. a. Thigh. 

b. Abdomen. b. Leg. ■ 

c. Foot. 



QUESTIONS. 

1. "What is hygiene ? 2. What are some of the things which it 
teaches us ? 3. What is anatomy ? 4. What does physiology teach 
us ? 5. Mention some of the things which it explains. 6. Explain 
the differences between these three branches : Anatomy, physiology, 
and hygiene. 7. Is there more than one form of animal life? 8. 
Give examples. 9. Do plants live ? 10. How do we know this ? 
11. Do plants ever have the power to move any of their parts ? 12. 
Give an example of this. 13. Mention the differences between 
plants and animals. 14 What is an organ of the body ? 15. Give 
examples of organs. 16. What is meant by the word " function ? " 
17. Give examples of this. 18. How do we divide the body? 19. 
Give an example of a part of the body. 20. What is a tissue ? 21. 
Give an example. 22. What are the very smallest subdivisions of 
the body called ? 23. What is a cell ? 24. What is a fibre ? 25. 
Name the three main parts of the body. 26. Into what parts can 
the head be divided ? 27. What is the trunk and what large cavi- 
ties does it contain? 28. Name the different parts of the upper 
limb. 29. Name the different parts of the lower limb. 



20 



ANATOMY, PHYSIOLOGY, AND HYGIENE. 




Back of Skull (Occiput) 

j Bones of Spinal Column 
J forming the Neck. 

Collar-bone (Clavicle). 

Upper End of Bone of Arm form- 
ing the Shoulder- joint. 

Bone of Arm (Humerus). 



Hip-bone. 

. Inner Bone of Forearm (Ulna). 
Outer Bone of Forearm (Radius). 

j Upper end of Thigh-bone 

j forming the Hip-joint. 

Bones of the Wrist (Carpus). 

Bones of the Hand (Metacarpus). 

j Bones of the Fingers (Pha- 
| langes of the Fingers). 

Thigh-bone (Femur). 

Knee-pan (Patella). 

Inner Bone of Leg (Tibia). 

Outer Bone of Leg (Fibula). 



. . . Bones of Ankle (Tarsus). 
Bones of Foot (Metatarsus). 

j Bones of Toes (Pha- 

1 langes of the Toes). 



Fig. 4.— The Skeleton, Viewed in Front. 



CHAPTER II. 
THE FKAMEWOBK OK SKELETON. 

17. The Skeleton is the name given to all the bones in 
the body taken together. These form a framework around 
which all the soft parts of the body are arranged, just as the 
walls and rafters of a building support the rest of it. In man, 
and in all the higher animals, the skeleton is on the inside, and 
the soft parts are placed around this bony framework ; in some 
animals, such as the crab and the lobster, the hard shell on the 
outside corresponds to the skeleton. 

18. Uses of Bones. — The uses of bone are : 

(1.) To give the body support and to keep it erect ; this 
we see especially in the spinal column and in the lower 
limbs. 

(2.) To protect soft parts which would otherwise be easily 
injured ; the brain, for instance, is enclosed in a sort of 
oval box formed by a number of flat bones joined to- 
gether ; in the same way, the heart and lungs are protected 
from injury by the bones which form the chest. 

(3.) To give great strength and hardness, and at the same 
time leave the part elastic ; as an example of this use, the 
wrist and the foot may be mentioned. In, the foot, for in- 
stance, we have many small bones joined together in such 
a way that though they are strong enough to bear the 
weight of the body, they are still elastic enough to allow 
us to jump upon the foot without injury. 

(4.) Lastly, bones are necessary for the purpose of mo- 
tion : For walking and running, for grasping objects, and 



22 ANATOMY, PHYSIOLOGY, AND HYGIENE. 



Bone of Forehead 

(Frontal). 
Upper End of Bone I 

of Nose (Nasal), j 
Cheek Bone (Malar) . 

Upper Jaw 

Lower Jaw 



The Breast-Bone 

(Sternum). 



Part of the Spinal") 
Column forming 
the Lower Part , 
of the Back. J 

Upper Part of the ( 
Hip-bone. f 

Upper End of the 
Thigh-bone, form- 
ing the Hip-joint. 



Bone of Right | 
Thigh (Femur). \ 



Right Knee - pan ) 
(Patella). f 



Inner Bone of 
Right Leg (Tibia). 



Lower End of "1 
Bones of Right ! 
Leg, forming An- j 
kle-joint. J 




Back of Skull (Oc- 
ciput). 



Bones of Spinal 
Column forming 
the Neck. 

Upper End of Bone 
of Arm, forming 
the Shoulder- 
joint. 

Bone of Arm (Hu- 
merus). 

One of the Ribs 
(Eighth). 



. . . The Elbow-joint. 

j Outer Bone of 
( Forearm (Radius). 

J Inner Bone of 
\ Forearm (Ulna). 
( Lower End or Tip 
•< of the Spinal 
( Column. 
.The Wrist (Carpus), 
j Bones of Hand 
\ (Metacarpus). 
Thumb. 

Index Finger. 



Bone of Left 
Thigh (Femur). 



.The Knee-joint. 



Outer Bone of Left 
Leg (Fibula). 



\ Bones of Arch of 
\ Foot (Tarsus). 
. .Bone of the Heel. 
Bones of the Toes 
(Phalanges of 
the Foot). 



Fig. 5. — The Skeleton, Viewed from the Side, with Outline of the Body. 



THE FRAMEWORK OR SKELETON". 23 

for performing the many actions required of us. The 
thigh-bones and the bones of the leg, for instance, are 
necessary for walking. Bones serve as points of attach- 
ment for muscles, and they are moved through the action 
of these muscles ; they simply carry out the will of the 
muscles, and these again are directed by our nerves and 
brain. 
19. Number of Bones. — There are two hundred bones in 
the human body. 




Fig. 6. — The Upper End of the Thigh-bone, where it Forms Part of the Hip-joint, Sawed 
through Lengthwise, Showing the Porous and Spongy Nature of Bone in Its Interior, and 
also the Commencement of the Central Canal for the Marrow. 

20. Forms of Bones. — Bones vary very much in form and 
in size. Some of them are long, as the thigh-bones (Fig. 21) ; 
others are small and short, such as the eight bones which form 
the wrist (Fig. 20) ; others are flat, as for example the bones 
forming the skull (Fig. 11) ; finally others are of very odd and 
irregular forms, such as the bones which form the spinal 
column (Fig. 16). 



24 



ANATOMY, PHYSIOLOGY, AND HYGIENE. 




21. Structure of Bone. — Each bone is surrounded by a 
very hard layer on the outside ; within this the bone is looser 

and is porous, having a large 
number of small spaces through 
which the blood-vessels run (Fig. 
The long bones, such as those 
of the arm, thigh, and fingers, 
are hollowed out in the centre, 
and in this canal we find a fatty 
substance called "marrow." -This 

Fig. 7.— A Thin Slice of Bone, Cut hollowing Out of the bone makes 

Crosswise, as Seen under the Microscope. 

it lighter and also stronger than 
it would otherwise be. Bones are closely covered by a tough 
membrane called the periosteum, which gives additional strength 
and protection to them. They are 
of a pinkish color during life, on ac- 
count of the small blood-vessels run- 
ning through them ; when dead, the 
color of bone changes to white. 

22. If we take a thin slice of bone, 
and look at it under the microscope, 
we will see a large number of dark 
spots, with small lines running from 
these (Fig. 7). They correspond to 
the minute spaces which exist even 
in the densest bone, and show that 
it is never entirely solid. 

23. Composition of Bone.— 
Bone is composed of two parts of a 
hard mineral substance containing a fig. s.-The outer Bone of the 

i-i-in-i. ip l Leg, Tied into a Knot after the 

great deal Ot lime, and 01 One part Hard Mineral Matter has been Dis- 

of a soft material like gelatin. The solved out by Cld ' 
mineral substance gives the bone its hardness ; the soft mate- 
rial makes it tough and elastic. To prove this we have only 
to dissolve out the mineral substance by a weak acid, and we 




THE FRAMEWORK OR SKELETON. 25 

find that we can now bend the bone in any direction because 
it has lost its hardness ; if it be long enough, we can even tie 
it in a knot without breaking it, as is shown in Fig. 8. 

24. If, on the other hand, we put the bone into the fire, this 
will drive off all the gelatin, and then the bone will have the 
same form as before, but will now be very brittle and crumble 
to pieces very easily. 

25. In the baby the bones consist very largely of a soft 
material — gristle or cartilage ; this is the reason why the baby 
cannot stand, or, if it is allowed to stand too soon, the bones 
of the legs may become bent, because they are not yet hard 
enough to bear the weight of the body. Gradually, as the 
baby grows, the hard matter is added. In younger persons 
the bones are always softer than in the aged, and therefore 
they do not break as easily. In old persons there is less gela- 
tin and a larger proportion of the brittle mineral substance 
than in youth ; hence the bones are more brittle and are more 
easily broken, or, as the surgeon would say, are more liable to 
fracture. 

26. Care of the Skeleton. — If we wish to have erect and 
graceful bodies when we grow up we must take care of them 
while we are young. It is while we are young that the bones 
are still soft, and thus easily shapened. We should always re- 
member to stand and to sit erect, with the chest thrown forward 
•and with the shoulders back ; in this way we will avoid stoop- 
ing and round shoulders. 

27. We should not wear any clothing which is too tight. How 
often do we see a misshapen chest in girls because they have 
worn dresses which were too tight. Fig. 72 is the picture of a 
chest which has become deformed through tight dress. If we 
compare it with Fig. 18, which represents a healthy chest, we 
cannot fail to notice the change. 

28. We must be careful to get shoes of proper size ; if they 
are too small or too pointed our feet will become deformed, our 
toes bent and crooked, and painful corns and bunions will 



26 ANATOMY, PHYSIOLOGY, AND HYGIENE. 

result. Such deformities are shown in Fig. 10. Girls should 
remember not to wear high heels, for these crowd the foot into 
the front part of the shoe, thus making the toes overlap each 
other. Shoes with high heels do not support the weight of the 
body properly, because they throw the upper part of the body 
forward. Another objection is the danger of accidents in fall- 
ing and of spraining the ankle when high heels are worn. 

29. Fracture of a Bone. — "When a bone is broken the acci- 
dent is quite a serious one ; it is called & fracture. The doctor 
is called and he sets the bone ; that is, he brings the two broken 





Fig. 10. — A Foot which has Become De- 
FlG. 9. — A Natural Foot. formed and Affected with Corns and Bunions 

as a Result of Tight and Ill-fitting Shoes. 



ends of the bone together, and keeps them in position by bandr 
aging them to a piece of thin board so that they cannot be 
moved ; then a soft material is formed between the two pieces, 
which gradually hardens and joins the two ends together. If 
properly taken care of, a broken bone becomes united again in 
several weeks, and is then as strong as it was before. If we 
happen to break a bone we must remember to keep as quiet as 
possible until the doctor arrives, so as not to move the injured 
part, or else we may make matters much worse. 

30. Effects of Stimulants and Narcotics. — Drinks con- 
taining alcohol, and the use of tobacco, may prevent our bones 



THE FRAMEWORK OR SKELETON. 27 

from growing to their natural size. Many boys smoke cigar- 
ettes because they think it makes them look big and manly. 
This is a mistake. No one will consider them so because they 
smoke, and the habit often results in preventing them from 
growing to their natural size. The bones of drunkards break 
more easily than do those of others. 

31. If we wish to be large and finely-built we must try to 
preserve our health, for when the health suffers the growth of 
the bones is interfered with. 

Having studied about bones in general, let us now examine 



THE DIFFERENT PARTS OF THE SKELETON. 

32. We may divide the skeleton into four parts : 
(1.) Bones of the head. 

(2.) Bones of the trunk. 

(3.) Bones of the upper limbs. 

(4.) Bones of the lower limbs. 

33. Bones of the Head. — The bones of the head taken 
together form the skull (Figs. 11, 12, and 13). The skull is 
made up of twenty-two bones. Eight of these are joined 
together at the upper and back part, forming an oval box of 
bone in which the brain is contained, and called the cranium. 
The front part of the skull, formed by the remaining fourteen 
bones, is called the /ace. 

34. The Cranium. — The portion of the cranium which 
forms the forehead is called the frontal bone (1, Fig. 13). In 
the lower animals, such as the dog and the cat, the forehead is 
very low and slanting ; in the negro race it is less slanting ; 
while in the white races it is almost upright. Usually the 
prominence of the forehead indicates the development of the 
brain ; in those who have spent much time in study it is usu- 
ally very prominent. Behind, the cranium is formed by the 
occipital bone (3, Fig. 13). Above, two bones, known as the 
parietal (2, Fig. 13), join together to form the top of the skull. 



28 ANATOMY, PHYSIOLOGY, AND HYGIENE. 

On the side of the head, just below where the hair ends, is a 
spot called the temple ; the bone which forms this part of the 
skull is called the temporal bone (4, Fig. 13). 

35. Most of the bones of the cranium have ragged edges look- 
ing like the teeth of a saw (Figs. 12 and 13), and when the 
bones are joined these teeth fasten the bones together just as if 
you spread out the fingers of one hand and then put them in the 




Fig. 11.— The Skull, Front View. 

spaces between the fingers of the other. In this way the bones 
are firmly united, and yet there is space between the edges so 
that they can give a little. This is very important, for if these 
bones could not give at all, every blow upon the head would 
injure the soft, delicate brain within. The muscles, skin, and 
hair on the head also serve to break the force of blows. 

36. The Face. — Looking at the skull in front (Fig. 11) we 
see two large openings just below the forehead ; they are 



THE FRAMEWORK OR SKELETON. 29 




FlG. 12.— The Human Skull, Looked at from the Side. 




Fig. 13.— The Bones of the Skull Separated. 1, Frontal; 2, Parietal; 3, Occipital: 
4, Temporal ; 5, Nasal ; 6, Malar ; 7, Upper Jaw ; 8, Lachrymal ; 9, Lower Jaw. 



30 



ANATOMY, PHYSIOLOGY, AND HYGIENE. 



known as the orbits and receive the eyes. Below and between 
these is the triangular opening of the nose, bounded above by 
two small bones (5, Fig. 13), the nasal bones. To the outer 

side and below the orbits are 
the bones which form the prom- 
inence of the cheeks, and are 
called the malar bones (6, Fig. 
13). At the lowest part of the 
face are the two jaws, the upper 
(7, Fig. 13) and the lower (9, 
Fig. 13) ; the upper jaw is firm- 
ly joined to the rest of the 
skull; the lower jaiv resembles 
a horse-shoe in shape, and is 
separate from the rest of the 
skull — of course, during life, it 
is connected to the sides of the 
face by strong bands and mus- 
cles. Each jaw has a circular 
row of teeth, about which more 
will be said in the chapter on 
Digestion ; between these two 
rows of teeth is the opening of 
the mouth. 

37. The skull rests upon the 
upper end of the spinal col- 
umn ; it is very movable, so 
that it can be bent forward or 
backward, or from side to side, 

Fig. 14.— The Spinal Fig. 15.-The Spinal aTlf q Pfiri l-, p fnrnPf! in miv flirpr- 
Column, as Seen Column as Seen anCl Can De rUinea m an J <*irec- 

from Front. from the Side. tion 

38. Bones of the Trunk. — The bones of the trunk are: 
the bones forming the spinal column, the hip-bone, the collar- 
bone, the shoulder-blade, the breast-bone, and the ribs. 

39. The Spinal Column. — This is the row of bones 




THE FRAMEWORK OR SKELETON. 



31 



which extends from the skull above to the lower limbs below. 
There are thirty-three of these bones piled one upon the other ; 
but in the grown person there are fewer, because the nine low- 
est bones unite so as to form two bones ; five go to form the 
upper one, called the sacrum, and four unite to form the tip of 
the spinal column, called the coccyx. So that there are really 
only twenty-six bones in the spinal column. Each of these 
twenty-six bones is called a vertebra, and all of them taken to- 
gether are known as the verte- 
brae. The spinal column is 
often called the backbone, on 
account of its extending along 
the middle of the back. The 
vertebrse are connected by 
circular plates of gristle or 
cartilage, and by fibres ; this 
cartilage and the fibres are 
elastic, and thus it is that 
our backbone is very mova- 
ble — we can bend it in any 
direction or twist it ; this is 
because this cartilage gives. 
This also explains why it is 
that at night we are a trifle 
shorter than in the morning, 
for the weight of the body has 

caused these plates of cartilage between the vertebrse to be 
compressed slightly, while after a rest during the night, they 
regain their usual thickness. There is an opening in each of 
the vertebrse, and when they are all in position, these openings 
connect and form a canal, the spinal canal, which runs all 
through the backbone. This canal holds the delicate spinal 
cord, from which nerves emerge through small openings on 
each side of the spinal column. At the upper end of the spinal 
canal it communicates with the cavity of the skull by means of 




-Three Vertebrse from the Lower 
Part of the Spinal Column, Separated. 



32 



ANATOMY, PHYSIOLOGY, AND HYGIENE. 



a large oval opening ; through this opening the spinal cord 
and the brain are directly continuous. If you run your finger 
along the middle of the back, you can feel projecting points ; 
these are the tips of the vertebrae. 

40. The Hip-bones (#", Fig. 21 and Fig. 17), are the two 
large and strong bones which are placed on each side of the 
lower end of the spinal column, forming with it a sort of basin 
which is called the pelvis. On the outer side of each hip-bone, 




Fig. 17. — The Pelvis, formed by the Lower End of the Spinal Column and the Hip-bones. 



at about its middle, will be noticed a deep, round depression ; 
in this fits the upper end of the thigh-bone. 

41. The Collar-bone, or Clavicle (Fig. 19, (7), is the 
curved bone which we see at the upper part of the chest in 
front, being connected with the breast-bone at its inner end. 

42. The Shoulder-blade, or Scapula (Fig. 19 B), is the 
large triangular bone which we see at the upper part of the 
chest, behind. It lies behind the upper ribs. At its outer 
angle is a round depression into which the upper ball-like end 
of the bone of the arm fits. 

43. The Br east- bone, is also called the sternum (Fig. 
19, S) ; it is a flat bone which is broad above and gradually 



THE FRAMEWORK OR SKELETON. 33 

tapers toward its lower end. It forms a strong guard to the 
front of the chest. Along its edges the ribs are attached on 
each side. 

44. The Ribs. — There are twenty-four ribs, twelve on each 
side. They are long, slender, curved bones, which form the 
outer boundary of the chest. They are very elastic. All the 
ribs are joined behind to the vertebrae of the back ; the first 
seven are attached to the breast-bone in front, and are called 




Fig. 18.— The Chest, or Thorax. 

true ribs ; the last five are not attached to the breast-bone 
in front, and are called false ribs ; the three upper of these, 
namely, the eighth, ninth, and tenth, are connected with carti- 
lage in front, but the last two are entirely free in front, and 
are called floating ribs. 

45. The Chest, or Thorax (Fig. 18). — It has already been 

explained that this is the large cavity just below the neck which 

serves to hold the heart and lungs. These organs are of great 

importance, and are nicely boxed in by the bones we have just 

3 



34 



studied ; namely, the breast- bone in front, the ribs on each 
side, the collar-bone above, and the backbone behind. There 

are, of course, spaces between 
these different bones, but in 
the living body these are filled 
by muscles. A flat sheet of 
muscle-tissue also bounds the 
chest below and separates it 
from another cavity situated 
just below it, the abdomen; this 
muscular partition is called the 
" diaphragm." 

46. Bones of the Upper 
Limb. — These are: the bone 
of the arm (humerus) ; the two 
bones of the forearm (radius 
and ulna) ; and the small bones 
forming the hand. 

47. The Bone of the Arm 
is a single bone, known as the 
"humerus;" it is a strong- 
bone and extends from the 
shoulder to the elbow. Its up- 
per end has an enlargement, 
shaped like a ball, which fits 
into the cup-shaped depression, 
seen at the outer angle of the 
shoulder-blade. 

48. The Bones of the 
Forearm. — There are two 
bones in the forearm, an outer, 
the radius, and an inner, the 

Fig. 19.— The Bones cf the Upper Limb. , mi v Wlipprl sidp bv 

S, Breast-bone (Sternum); C, Collar-bone Ulna. Hiey aie piaceQ Side Dy 
(Clavicle); B, Shoulder-blade (Scapula); A, .-, ,, p hpf.WPen them 

Bone of Arm (Humerus); F. Bones of Fore- Side, Uie Space DCIWCeu LLLtJlll 

Bonei^Hand 71 "^ ' W ' BoneS ° f Wri " t; ^ being filled up by a membrane 




THE FRAMEWOEK OR SKELETON. 35 

and by muscles. ■ They extend from the elbow to the wrist. 
In twisting the forearm the radius revolves around the ulna, 
which is the more stationary of the two. 

49. The Bones of the Wrist and Hand. — There are 
twenty-seven bones in each hand. The hand may be divided 
into three parts : The wrist or car- 
pus, the palm or metacarpus, and 
the fingers or phalanges. The wrist 
is the most solid part and is made 
up of eight small bones, more or 
less rounded or cubical in shape, 
closely held together by tough 
bands ; this arrangement serves to 
make the wrist very strong and 
still very light. The bones form- 
ing the palm of the hand are five 
in number. Each finger has three 
bones, the end of one being joined 
to that of the other, except the 
thumb, which is shorter and has 
but two such phalanges; this ar- 
rangement of the bones of the fin- 
gers allows them to move very 
dexterously. 

50. Bones of the Lower 
Limb. — These comprise the thigh- 
bone (femur), the bones Of the leg Fio 20,-The Bones of the Wrist and 

x,/ 7 Hand. Above is also seen the lower 

(tibia and fibula), the knee-pan (pa- ends of the radius and ulna, taking 
] part in forming the wrist-joint. 

tella), and the bones ot the foot. 

51. The Thigh-bone, or Femur, is the largest and strong- 
est bone in the body, and is surrounded by more muscle than 
any other bone. Where it is attached to the hip-bone it has a 
large spherical part called its head, and this forms an angle with 
the rest of the bone by a part called the neck. Below, the thigh- 
bone joins with the bones of the leg and with the knee-pan. 




36 



ANATOMY, PHYSIOLOGY, AND HYGIENE. 



52. The Knee-pan, or Patella, 

is the small, round, flattened bone 
which can be felt at the knee. It 
serves as a protection to the joint, 
and often saves it from injury in falls 
and blows. 

53. The Bones of the Leg. — 
There are two bones in each leg. The 
inner bone is the shorter and stronger 
of the two, and is called the tibia. 
The outer bone is longer and more 
slender; it is called the fibula. These 
two bones, placed side by side, extend 
from the knee to the ankle. 

54. The Bones of the Foot. — 
Each foot is formed by twenty-six 
bones, one less than in the hand. 
Seven of these form the solid back 
part of the foot, called the tarsus, 
which includes the heel ; five form the 
arch or instep, also known as the met- 
atarsus ; and the remaining fourteen 
form the toes or phalanges. Thus, it 
will be seen, that there are as many 
bones in the toes as in the fingers ; 
but the toes are much less movable, 
being simply intended for support of 

— the body and for walking ; however, 
the Lower when they are trained to do other 
lower end of things, they may become almost as 
Column (sa- nimble as the fingers are. The heel is 
cyx) ; it, "the the most solid part of the foot and the 
Se P "T°high- strongest. The sole of the foot, be- 
fpaLiLT'lhe^'ones of ?heTeg tween the heel and the toes, forms an 
( oIih e a Fo n o d t. Fibula); F ' the B ° nes arch at the inner border of the foot; 




THE FRAMEWOKK OR SKELETON. 37 

this arch breaks the force of jumps from heights. If we are 
compelled to jump from a height, there is the least disagree- 
able effect and danger to the body if we alight on our toes, or 
just behind the toes ; when we reach the ground upon the 
heel, the shock is transmitted through the entire body, and 
gives rise to a very disagreeable sensation, and even to injury. 



SYNOPSIS. 

Position — 1. Internal in higher animals. 

2. External in some of lower animals. 
Uses of the bones : 

1. Support to rest of body. 

2. Protection to delicate organs. 

3. Strength and hardness. 

4. Motion, by serving as points of attachment for muscles. 
Number of Bones : Two hundred. 

Forms of Bones : 

1. Long. 2. Short. 3. Flat. 4. Irregular. 

Structure of Bone : 

1. Outer dense layer. 

2. Interior porous and light. 

3. Central canal rilled with marrow in long bones. 

4. Blood-vessels pass through it, giving pink color during 
life. 

5. Covered by membrane (periosteum). 
Composition of Bone : 

1. Animal matter — About one-third in amount. 

Larger proportion in early life. 
Gives toughness and elasticity. 

2. Mineral matter — About two-thirds in amount. 

Larger proportion in advanced life. 
Gives rigidity. 
Care of the Skeleton : 

1. Avoid faulty positions, to prevent stooping and round 
shoulders. 

2. Avoid tight clothing, to prevent deformed chests. 



38 



3. Avoid faulty shoes, to prevent deformities of the feet, corns, 
bunions, and accidents. 

4. Extensive indulgence in stimulants and narcotics (alcohol 
and tobacco) may prevent bones from growing to natural size. 

5. When general health suffers, growth of bones is inter- 
fered with. 

Fracture of a Bone : 

1. " Setting " the bone. 

2. To prevent further injury, the broken part should be kej)t 
quiet until the doctor arrives. 

3. Method of healing by material binding the two ends to- 
gether. 

Parts of the skeleton : 

1. The Head : 

a. Cranium — 1. Frontal. 

2. Parietal. 

3. Occipital. 

4. Temporal, etc. 

b. Face — 1. Nasal. 

2. Malar. 

3. Upper jaw. 

4. Lower jaw, etc. 

2. The Trunk: 

a. Spinal column (composed of 33 vertebras). 

b. Chest (formed by vertebrae, sternum, clavicle, and ribs). 

c. Eibs— 1. True. 

2. False (including two floating ribs). 

d. Collar-bone (Clavicle). 

e. Shoulder-blade (Scapula). 
/. Breast-bone (Sternum). 

g. Pelvis (formed by lower end of spinal column and 
hip-bones. 

3. The Upper Limb : 

a. Bone of arm (humerus). 

b. Bones of forearm — 1. Radius. 

2. Ulna. 

c. Bones of hand — 1. Wrist (Carpus). 

2. Palm (Metacarpus). 

3. Fingers (Phalanges). 



THE FRAMEWORK OR SKELETON". 39 

4. The Lower Limb : 

a. Bone of thigh (Femur) . 

b. Knee-pan (Patella). 

c. Bones of the leg — 1. Tibia. 

2. Fibula. 

d. Bones of foot — 1. Heel (Tarsus). 

2. Arch (Metatarsus). 

3. Toes (Phalanges). 



QUESTIONS. 

1. What is meant by the word "skeleton?" 2. How does the 
skeleton of a crab and lobster differ from that of man ? 3. What are 
the uses of bone ? 4. How many bones are there in the human 
body ? 5. Mention the different forms of bones. 6. Which part of 
the bone is the hardest ? 7. How does the inner part of the bone 
differ from the outer layer ? 8. What is marrow ? 9. Of what sub- 
stances is bone composed? 10. How can you show that bone is 
made up of these two substances ? 11. How do the bones of a baby 
differ from those of a middle-aged man ? 12. How do the bones of 
an old man differ from those of a younger man ? 13. Tell something 
about the care of the skeleton. 14. Why is it necessary to sit and 
to stand erect ? 15. What happens when we wear our clothing too 
tight ? 16. What is a fracture ? 17. What effect may alcohol and 
tobacco have upon our skeleton ? 18. What effect does smoking 
have upon the size of boys ? 19. Will the growth of our bones 
take place properly if our health is poor? 20. Into what four dif- 
ferent parts can we divide the skeleton ? 21. What are the bones 
of the head taken together called? 22. What is the cranium and 
how many bones join to form it ? 23. How are the bones of the 
cranium united ? 24. Where is the frontal bone ? 25. What does 
the prominence of the forehead show ? 26. Where are the orbits ? 
27. What is peculiar about the lower jaw ? 28. Name the bones of 
the trunk. 29. What are the vertebrae ? 30. How many are there ? 
31. How are they connected together? 32. WTiat opening is there 
in the spinal column ? 33. What can you say about the hip-bones ? 
34. Where is the collar-bone ? 35. Where is the shoulder-blade ? 
36. What is another name for the breast-bone ? 37. What is its 



40 ANATOMY, PHYSIOLOGY, AND HYGIENE. 

use? 38. How many ribs are there? 39. What does a rib look 
like? 40. Which are the true ribs? 41. Which are the false ribs? 

42. What is a floating rib, and which ribs are called floating ? 

43. What is the chest, and what does it contain ? 44. What is 
another name for it ? 45. What bones form the boundaries of the 
chest ? 46. What is the diaphragm, and what cavities does it sep- 
arate ? 47. What bones are there in the upper limb ? 48. How 
many bones are there in the arm ? 49. How many in the forearm ? 
50. How many bones are there in the hand ? 51. How is the wrist 
formed ? 52. How many bones are there in each finger ? 53. How 
many bones are there in each lower limb ? 54. Which is the largest 
bone in the body ? 55. Describe the thigh-bone. 56. How many 
bones are there in the leg ? 57. Describe the knee-pan and its use. 
58. How many bones in the foot ? 59. Which are the more movable, 
the toes or the fingers? 60. Which is the strongest part of the 
foot ? 61. In jumping from a height, upon what part of the foot 
should we alight, and why ? 62. What are the dangers of high 
heels? 63. What are the effects of too small or badly-formed 
shoes ? 



CHAPTER III. 
THE JOINTS. 

55. Wherever two or more bones meet we have a joint. Joints 
are necessary in order that one part of the body may move 
independently of the other. If this arrangement did not exist 
we would have to move the entire body whenever we wanted 
to move any part of it. If you observe how a man walks when 
his knee-joint, for instance, is stiff and cannot be used, you will 
appreciate how useful joints are. The more joints there are in 
any part of the body the more movable is that part ; notice, for 
instance, how movable the fingers are and how many joints 
there are in the hand. 

56. According to the amount of motion which they permit, 
joints are divided into three classes : 

(1.) Immovable joints, in which there is no visible 
motion. 

(2.) Slightly-movable joints, in which there is slight mo- 
tion only. 

(3.) Movable joints, in which there is free motion. 

57. Immovable Joints.— The best example of this form of 
joint is seen in the skull. The flat bones of the skull are 
fastened together by means of the small projections from their 
edges ; such joints are called sutures. They are very well 
adapted to what is required here, because being closely joined 
they make a strong box of the bones of the skull, and yet they 
are capable of a very little motion, enough to break the force 
of blows upon the head ; in this way they serve as additional 
protection to the brain. 

58. Fig. 22 shows the sutures which we find on the upper 
surface of the skull. In front, joining the frontal bone with 



42 



ANATOMY, PHYSIOLOGY, AND HYGIENE. 



the two parietal bones, we have a suture which extends across 
the skull from one side to the other ; it is called the coronal 
suture, from the Latin word corona, which means "a crown," 
because the front part of the crown of a king is supposed to 
rest upon this line. Behind, where the occipital bone meets 
the two parietal bones, is another suture, called the lambdoid, 




Fig. 22. — View of the Skull from Above, Showing the Sutures. 



on account of its resemblance to the Greek letter lambda (A). 
Between these two sutures, the coronal and the lambdoid, is 
another which connects the two parietal bones ; it is called the 
sagittal suture, from the Latin word sagitta (an arrow), because 
it was thought to join the coronal suture as an arrow meets the 
string* of a bow. 

59. Slightly-movable Joints. — In these joints a fair 
amount of motion is allowed, but much less than in the next 
class — the movable joints. We find examples of slightly-movable 
joints between the different vertebrse forming the spinal column. 

60. Movable Joints. — These are the most numerous and 



THE JOINTS. 43 

the most interesting. In all movable joints the same general 
arrangement exists: the ends of the bones forming the joint 
are covered with gristle or cartilage — this is a dense, semi- 
transparent substance which is much softer than bone — it acts 
as a sort of cushion to the ends of the bones in the joint, so 
that they are not bruised or injured when the joint is moved, 
or when the ends are brought together forcibly, as in jumping. 
If two surfaces rubbing against each other were dry they would 
soon be rubbed off; hence it is necessary to keep a joint moist 
all the time. In machinery this is accomplished by oil. In the 
living body the same thing is done by a yellowish fluid looking 
like the white of an egg, which constantly covers the ends of 
these bones ; this fluid is given off from the inner surface of a 
sort of sac which lines all movable joints. This sac or mem- 
brane is called the synovial membrane, and the fluid which 
it gives off is called synovial fluid. The ends of the bones form- 
ing joints are held in place and connected by strong bands 
of tough tissue, which pass from one bone to the other, and are 
called ligaments. This is shown in Fig. 23, which represents a 
joint cut in two ; the bands on the outside, one on each side, 
passing from the upper to the lower bone, are the ligaments. 
Sometimes these are so extensive as to surround the entire joint, 
and thus be a sort of cover to it. This entire covering is 
called the capsular ligament, because it is like a capsule ; this is 
seen in Fig. 24. 

61. Varieties of Movable Joints. — There are four varie- 
ties of movable joints : 

(1.) Gliding-joint — in which one bone slides upon the 
other, as is seen between some of the small bones forming 
the wrist. 

(2.) Hinge-joint — in which one bone swings forward and 
backward from the end of the other, just as a door opens 
and closes upon its hinges. A good example of this form 
of joint is seen in the connection of the arm with the fore- 
arm at the elbow. 



44 



ANATOMY, PHYSIOLOGY, AND HYGIENE. 



(3.) Pivot-]omt — in which one bone turns upon the other 
by an arrangement resembling a pivot. This is seen in 
the connection between the skull and the upper end of the 
spinal column. 




Fig. 23. — One of the Movable Joints Sawed 
through Lengthwise, with the Different Parts 
in their Proper Position, thus Showing the 
General Arrangement in Joints. 




Fig. 24.— The Hip-joint, Showing the 
Capsular Ligament Surrounding the Junc- 
tion between the^Hip-bone Above and the 
Thigh-bone Below. 



(4.) Ball-and-socket -joint. This is a form of movable joint 
in which the greatest amount of motion is allowed. One 
bone ends in an enlargement like a ball ; this fits into a 
hollowing-out of the other bone, hence the term " ball- 
and-socket." Examples of this form of joint are seen in 
the shoulder and hip. 
62. Accidents to Joints.— When one of the bones which 
forms the joint is not in its correct position and no longer fits 
on the end of the other, we may say it is out of joint or dis- 
located. This is a very painful accident. The bones must be 
put in joint again by the surgeon ; often the capsular ligament 
is torn. The accident usually is the result of falls ; many such 
falls take place in getting off street-cars, especially if the car 



THE JOINTS. 45 

has not come to a complete stop, and the person does not re- 
member to get off facing the horses. 

SYNOPSIS. 

Definition — The place of meeting of two or more bones. 
Uses — To allow greater freedom of motion. 
Varieties — According to amount of motion permitted : 

1. Immovable — no visible motion — sutures : 

a. Coronal. 

b. Lambdoid. 

c. Sagittal, etc. 

2. Slightly-movable — slight motion. 

3. Movable — free motion. 

a. Ends covered with cartilage. 

b. Upon this is synovial membrane. 

c. Kept lubricated by synovial fluid. 

d. Bones connected and held in place by ligaments. 

e. Four different forms : 

1. Gliding-joint. 

2. Hinge-joint. 

3. Pivot-joint. 

4. Ball-and-socket-joint. 
Accidents — Dislocations — "out of joint." 

QUESTIONS. 

1. What is a "joint" in anatomy? 2. "What advantage is there 
in having joints in the body ? 3. What classes of joints are there ? 
4. Give an example of an immovable joint. 5. What is a "suture?" 
6. Name the most important sutures of the skull, and describe each 
one. 7. Give an example of a slightly -movable joint. 8. Describe 
the general arrangement in movable joints. 9. How are such joints 
kept moist? 10. What is cartilage ? 11. What are ligaments ? 12. 
How are the ends of bones forming joints held in place ? 13. What 
is a capsular ligament? 14. What forms of movable joints are 
there? 15. What is a gliding-joint? 16. Give an example. 17. 
What is a hinge-joint ? 18. Give an example. 19. What is a pivot- 
joint? 20. Give an example. 21. What is a ball-and-socket-joint ? 
22. Give an example. 23. What is a dislocation ? 



46 ANATOMY, PHYSIOLOGY, AND HYGIENE. 




Fig. 25.— The Muscles of the Human Body (the Skin having been Removed). 



CHAPTER IV. 
THE MUSCLES AND MOTION. 

63. Thus far we have been studying the framework of the 
body and we found this to consist of about two hundred bones, 
which together we spoke of as the skeleton ; we found also that 
these bones were held together by tough tissues, which we 
called cartilage and ligaments ; we saw that there were a great 
many joints, so that one bone could move upon the other. All 
these formed the framework. Now will be considered some of 
the tissues which cover the framework, or fill up the spaces 
between the different parts of the skeleton. The first of these 
to be considered are the muscles ; we will consider particu- 
larly the great mass of muscles which we find covering the 
skeleton. 

64. Function or Work of the Muscles. — Muscles give 
us the power of moving the different parts of the skeleton. Our 
skeleton would be of very little value to us if we could not 
move the different bones ; just as the sails of a ship would be 
of little use unless there were ropes and pulleys to hold and 
move them. 

65. Description of Muscle-tissue. — Muscles are the red 
masses which we commonly call flesh. What the butcher 
sells as meat is a mass of muscles from some animal. When 
we eat roast beef for our Sunday dinner we are consuming a 
number of large muscles from the ox. Muscle is of a blood- 
red color. We can separate each muscle into small fibres, 
which are thread-like bodies joinect side by side to form a 
fleshy mass which we call muscle. If we look at such a muscle- 



48 



ANATOMY, PHYSIOLOGY, AND HYGIENE. 




Fig. 26.— A Piece of 
rated into its Fibres and Showing the 
Striped Appearance of the Fibres. (Mag- 
nified several hundred times.) 



fibre under a strong microscope we see a peculiar striped ap- 
pearance, which shows that each muscle-fibre is composed of a 

large number of smaller pieces 
joined together at their surfaces 
(Fig. 26). 

66. Tendons. — Muscles are 
strong, but still they are too soft 
to be attached directly to bone — 
they would not hold. So that we 
have strong, tough cords, known 
as tendons, which are attached to 
the muscles and connect them 
with the bones. The 
tendons are white and 
shining and hence can 
easily be distinguished 
from the muscles. 
They are of great 
strength, and it is very rare for any of them to 
break. The central, thick, fleshy part of a muscle 
is called its belly. In Fig. 27 the belly of the mus- 
cle is marked B, the ends or tendons T. If you 
feel the fleshy mass on the front of the forearm, 
you are feeling muscle. But if you put your finger 
at the wrist, and open and close your hand, you 
will feel hard cords move ; these are the tendons 
of the muscles of your forearm and serve to attach 
the muscles to the bones of your fingers. 

67. Fat. — The different muscles always have a 
little fat mixed with them which cannot be sepa- fig. 27. — a 
rated. But, besides this smaller quantity, there m°u s'c i e . c b^ 
is more or less fat in layers between the different Kions . T ' T ' 
muscles ; there is also fat covering the muscles and 
between the muscles and the skin. Meat free from fat is said 
to be lean. 



1 



THE MUSCLES AND MOTION. 49 

68. Uses of Fat. — A certain amount of fat is necessary ; it 
is useful in the following ways : 

69. (1.) It keeps the body warm. Fat does not allow the 
heat of the body to pass out readily, and so it protects us from 
the cold. 

70. (2.) It protects the body from pressure. Just beneath 
the skin is a layer of fat ; this is thick at some places, and thin 
at others. Where the body is exposed to much pressure the 
layer of fat is thick, preventing us from feeling the weight of 
the body. In the palms of the hands and the soles of the feet, 
for example, there is much fat ; otherwise our hands and feet 
would ache every time we used them considerably. 

71. (3.) Fat is a sort oifood. When persons are deprived of 
food they may live for a number of days ; the fat of their bod- 
ies is changed into nourishment which the blood takes up and 
furnishes to different parts of the body. As examples of this 
we have cases in which persons who were shipwrecked, or who 
stowed themselves away in the hold of a ship so as to steal a 
passage, have survived many days. The tissue which suffers 
most is the fat ; this disappears, and on this account such per- 
sons rapidly become very thin. 

72. (4.) Another use of fat is to give a fine appearance to the 
body : it fills up the uneven spaces that would be left between 
muscles and bones. If it were not for this the entire body 
would be uneven and lumpy. In the baby, where the muscles 
are small and undeveloped and there is considerable fat, the 
outline of the body is nice and round. As the baby gets older 
the muscles become larger, and the amount of fat smaller, and 
the body is no longer as plump and rounded. Where the 
muscles are well-exercised much of the fat is absorbed and the 
muscles stand out prominently. But still there is always some 
fat present. 

73. Kinds of Muscle-tissue. — Muscle-tissue is of two 
kinds. One variety, to which most muscles belong, is under 
the control of the will; hence such muscles are known as volun- 

4 



50 ANATOMY, PHYSIOLOGY, AND HYGIENE. 

tary muscles — directed by the will. Such muscles remain in a 
state of rest until we desire to use them. All the muscles on 
the outside of the body are of this class. The muscles of our 
arm, for instance, remain at rest during sleep, and at other 
times when we do not care to make use of them. Voluntary 
muscle-tissue appears striped when looked at under the micro- 
scope. 

74. The other class of muscles we call involuntary, that is, 
not directed by the will. These muscles are situated inside the 
body ; as examples may be mentioned the heart, the layer of 
muscles which is found in the walls of the stomach and intes- 
tines, and the muscular fibres which we find in the walls of 
the arteries and by which these blood-vessels are made to con- 
tract. We cannot control the action of these muscles ; they 
act without our being conscious of it, and it is well that it is 
so. Take the heart, for instance ; day and night it is at work 
pumping the blood into the blood-veseels, to be carried all 
over the body. If we had to watch over this organ, to see that 
it kept on beating, we would always have to stay awake ; and 
if we were careless and fell asleep, and the heart stopped be- 
cause we were not directing it to keep on beating, life would 
soon cease. As another example, let us look at the working of 
the stomach. After food enters this organ the muscular fibres 
in its wall begin to contract and move the food about, so as to 
break it up into finer particles ; this is done without our know- 
ing anything about it, and without our being able to control 
it. Involuntary muscle-tissue presents no striped appearance 
under the microscope. 

75. Mixed Muscles. — Some muscles belong partly to one 
class and partly to the other ; for instance, the muscles be- 
tween the ribs, which move the latter in breathing. These 
act all the time ; yet we may not be aware of their action, which 
continues whether we are asleep or awake. Still we can stoj) 
breathing for a very short time, or we can breathe more rap- 
idly than is natural for a very short time — but only for a short 



THE MUSCLES AND MOTION. 



51 



time. These muscles are partly voluntary and partly involun- 
tary. 

76. How Muscles Act. — "When a muscle acts we say it 
" contracts ; " as a result of this it causes some part of the body- 
to move. If we watch a muscle while it is contracting we find 
it becomes shorter, broader, thicker, and at the same time 





Fig. 28.-4, a Muscle at Rest ; B, the Fig 29.— The Action of the Biceps Muscle 

same Muscle Contracted. It has become of the Front of the Arm. (The dotted fig- 
shorter, broader, and thicker. ure shows the effect of the contraction upon 

the position of the forearm.) 



harder. Place your left hand upon the front of your right 
arm ; now bend your fingers into the palm of your right hand 
and then bend your right forearm upon the arm ; you will feel 
the muscle on the front of the arm become hard and swell up 
— it has become shorter, broader, and thicker. Since the mus- 
cle cannot break loose from its attachment to bones, it must 
bring these bones nearer together when it shortens. Fig. 28 
shows a long, fleshy muscle at rest (A), and the same muscle 



52 ANATOMY, PHYSIOLOGY, AND HYGIENE. 

after contraction (having become shorter, thicker, and broader), 
to the right (B). In Fig. 29 the manner in which the contrac- 
tion of a muscle causes motion is shown. The picture illus- 
trates the biceps muscle on the front of the arm. It is attached 
above to the shoulder-blade (which is the fixed point), and be- 
low to one of the bones of the forearm (the movable attach- 
ment). The dotted figure shows the muscle after it has con- 
tracted — in order to shorten it must bend the forearm, so as 
to bring its two points of attachment nearer together. 

77. Though muscles have the power to contract, they cannot 
do this unless we direct it ; the order to act comes from the 
brain. If the brain wishes a certain muscle to act, it sends it 
a message, and then the muscle responds. This message goes 
from the brain to the soft, whitish matter in the canal running 
through the centre of the spinal column, known as the spinal 
cord ; from the spinal cord the message is sent directly to the 
muscle by certain white threads, which we call nerves. 

78. This whole arrangement is very much like a telegraph 
office : the brain corresponds to the office to which messages 
come and from which messages are sent out, and the nerves 
we may liken to the telegraph wires or messengers which carry 
the despatches. The following example will illustrate this : 
Suppose you see an orange on the table before you. The eye 
sends a message to the brain, by means of the nerve of the eye, 
that the orange is there. You are heated and thirsty, and 
would like to eat the orange. The brain then sends out a mes- 
sage to the muscles that move your fingers and to those that 
move your arm that they are to seize the orange ; then they 
do so. The message from the brain was carried down through 
the nerve-tissue in the backbone, the spinal cord, then through 
the nerves of the arm to their smallest branches, which pass to 
the muscles. 

79. Although the muscles contract, and thereby cause the 
movement of the arm, forearm, and fingers, they are only 
the servants of the brain and nerves ; without an order from 



THE MUSCLES AND MOTION. 53 

the brain through the nerves they could not move. This is 
proven by the fact that when, from an injury, the nerves of the 
forearm are cut across, the muscles of the forearm and hand 
become lame, and we say they are paralyzed ; if we examine 
them we may find no change ; but they can no longer receive 
orders to act from the brain, and on this account are motion- 
less. 

80. Ordinary Muscular Movements are very Com- 
plex. — It is so easy for us to make use of our muscles that 
we are apt to believe every act which they perform is very sim- 
ple, but this is not the case. Even the very simplest acts in- 
volve the use of a great many different muscles. When we 
walk, for instance, we do not even give it a thought, yet very 
many different muscles are acting, each one with great skill 
and nicety. It is on this account that man cannot construct ma- 
chinery that will perform many of the things done by his hands. 
No machine could be constructed, for instance, that could 
write, or draw, or paint, and resemble the work done by hand. 
Even when we stand there are a number of muscles at work 
balancing the body. After standing a long while, owing to the 
fact that these muscles become worn out, we feel tired. 

81. Groups of Muscles. — Usually we find that muscles 
occur in sets or groups, and that one set accomplishes just the 
opposite action from the other. Thus the muscles on the front 
of the forearm serve to close the fingers and hand, while those 
on the back of the forearm serve to open them. The large 
muscle on the back of the arm, called the triceps, straightens 
out the forearm, while the thick muscle in front of the arm, 
called the biceps (Fig. 30), bends the forearm upon the arm. 

82. All the different expressions of the face are produced by 
the action of the small muscles of the face. When they draw 
up the corners of the mouth they give rise to a look of pleasure 
and smiling ; or they draw down the corners of the mouth and 
produce an expression of sadness and displeasure. They may 
wrinkle the forehead horizontally and make the face look in 



54 ANATOMY, PHYSIOLOGY, AND HYGIENE. 




Fig. 30.— The Muscles of the Front of the 
Chest, Arm, and Forearm. The fan-like 
muscle above and to the left is the " pec- 
toralis;"' in the centre of the arm is seen 
the " biceps." 



doubt, or by wrinkling it verti- 
cally produce a frown. There 
are many other varieties of ex- 
pression. The expression of the 
face soon becomes that which 
the person himself habitually 
makes. If you look sullen and 
angry all the time the face will 
soon have this expression, be- 
cause the muscles become so ac- 
customed to acting in this way 
that they cannot do otherwise. 
In the same way you may have 
a constant silly expression, if 
you act the part of a fool every 
time you are with your com- 
panions. Some children are in 
the habit of twisting their eyes 
so that they look cross-eyed ; 
this they often do to make their 
friends laugh ; they should re- 
member that from constantly do- 
ing this the eyes may be injured. 
83. Number of Muscles. 
— There are about three hundred 
muscles on each side of the body, 
making about six hundred in all. 
Nearly all the muscles occur 
in pairs, that is, are the same 
on one side as on the other. 
A few muscles which exist in 
the middle line of the body 
are single. 

84. Shape of Muscles. — 
Muscles vary greatly in shape. 



THE MUSCLES AND MOTION. 



55 



The most frequent form is that of a long, fleshy bundle with a 
tendon at either end for fastening it to bone. Sometimes they 
are flattened and placed in layers, as is the case in the muscles 
of the wall of the abdomen. Some muscles consist of flattened 
bundles which come together toward a single point like a fan ; 
such is the muscle of the temple — the temporal muscle. Other 
muscles are square-shaped, and still others form a circular 
ring ; so that there is great variety in the shapes of muscles. 

85. Size of Muscles. — Here, too, there are the greatest 
differences. Some of the muscles in the interior of the ear are 
only a fraction of an inch in length. Some of those of the eye 
are about an inch in length, while the longest muscle is one 
which extends from the hip to below the knee ; it is over two 
feet in length. Between these two extremes there are many 
different sizes. 

86. A Few Important Mus- 
cles. — It is not necessary for you to 
remember the names of many of the 
muscles, but there are a few which 
are worth knowing about, because 
they are important, and because we 
often see them mentioned in books 
and in newspapers. They are the fol- 
lowing : 

87. The Biceps is the large fleshy 
muscle on the front of the arm, which 
bends the forearm upon the arm 
(Figs. 30 and* 31). It can be felt 
upon making this motion. 

88. The Triceps is the muscle of 
considerable size which can be felt 
upon the back of the arm. It serves 

to straighten out the forearm after the biceps has bent it 

89. The Chest-muscle, or Pectoralis (Fig. 30), forms the prom 
inence at the upper part of the chest on each side. It is trian 




Fig. 31.— The Biceps and Tri- 
ceps Muscles. 



56 



ANATOMY, PHYSIOLOGY, AND HYGIENE. 






■ 



gular in shape, like a fan. It draws the arm inward across the 
chest. 

90. The Diaphragm is the sheet of muscle which separates 
the cavity of the chest from that of the abdomen. It is of 
great importance, and is one of the principal muscles concerned 
in breathing ; it is an involuntary muscle. 

91. The Tendon of Achilles. — This is 
the strong, thick cord which you can feel at 
the back and lower part of the leg, just above 
the heel. It is the end of a very large and 
powerful muscle which raises the heel when 
we walk. It has received its name from the 
following story : Achilles was a Grecian hero. 
There was supposed to be a river, the Styx, of 
which it was said that whoever bathed in its 
waters could not be wounded. The mother of 
Achilles wishing to preserve her son from all 
future danger, dipped him into this river Styx, 
holding him by the heel. All parts of his body 
were wet except the heel by which he was held, 
and at this place he is said to have received his 
death-wound. 

92. The Care of Muscles. — The muscles 
form such a large part of the body that they 
soon show changes whenever our health is poor. 
During sickness they waste away and become 
smaller. Even after being confined to bed for a 
few days only we are surprised how weak we 
feel on getting up, and how difficult it is for 
us to stand. During this short period our 
muscles have become weaker because we could 

not exercise them. So that in order to get strong muscles 
they must be exercised well. 

93. Exercise. — Look at the arm of a blacksmith and see 
how well-developed his muscles are. This is because he is 



Fig. 32.— The Mus- 
cles of the Back of 
the Leg, showing Be- 
low (* *) the Tendon 
of Achilles. 



THE MUSCLES AND MOTION". 57 

constantly exercising them. In the same way the legs of a 
man who walks or runs a great deal will be well developed ; 
they become prominent and hard. It is a fine sight to see a 
man who has large muscles which stand out and make him look 
strong and manly. Such a man is not as apt to get sick as 
another ; he feels stronger and is more useful in the world 
because of his strength. 

94. All children should exercise regularly and sufficiently. It 
is not enough to walk slowly to school each day ; if this is all 
the exercise a person takes his muscles will become small and 
weak, and he will become delicate. Children should have at 
least two or three hours exercise each day. The best exercise is 
that which is taken in the open air. 

95. Playing with one's companions is the best kind of exer- 
cise, because it rests the mind and exercises the body at the 
same time. Walking fast, moderate running, rowing, swim- 
ming, skating, bicycle -riding, and playing base-ball, foot-ball, 
tennis, and. croquet are all good forms of exercise. 

96. We must remember to quit exercise when we begin to 
feel tired, for this is a sign that we have exercised enough 
and need rest. If exercise be continued too long it is harmful 
instead of beneficial. Often we see girls jumping the rope — 
one is trying to outdo the other in the number of times she 
jumps without stopping ; many of the girls will be so tired that 
they can scarcely continue, and yet they go on simply to outdo 
their companions. They do themselves great harm by this 
excessive exercise ; even death has resulted from it. 

97. We should, also avoid all violent exercise, for this does 
more harm than good. When boys try to lift heavy weights 
which would be a task even for men, or do too difficult feats in 
the gymnasium, producing too great a strain upon the mus- 
cles, it only harms them instead of causing them to improve in 
strength. 

98. Effects of Alcohol and Tobacco on Muscles.— Of 
all enemies to the development of muscle there are none greater 



58 ANATOMY, PHYSIOLOGY, AND HYGIENE. 

than alcohol and tobacco. This is so well known that all persons 
who " train " in order to accomplish great physical feats requir- 
ing unusual strength and the best of health, give up all use of 
tobacco and either use very little alcoholic drink or none at all. 
What alcohol is will be explained in the next chapter ; it will 
be sufficient to say here that all those drinks which, taken in 
considerable quantity, cause men to become intoxicated, con- 
tain alcohol and are called " alcoholic drinks." 

99. The word train also requires an explanation. It means 
to live in the most healthy way ; to go to bed early and rise 
early, to eat the most digestible and strength-giving food, to 
take plenty of out-of-door exercise, to avoid all tobacco, and to 
abstain entirely or almost so from drink containing alcohol. 
All this is done so as to put the person in a very fine, healthy 
condition, and to develop his muscles, so that he may be as 
strong as possible. 

100. Everyone has probably heard of the great boat races 
which take place every year between Columbia and Harvard 
Colleges, and between Harvard and Yale Colleges. There is 
great rivalry between the colleges, and of course each one likes 
to win the race. Each of these crews "train" throughout the 
winter and spring until the day of the race, so as to make them 
strong and increase their chances of winning. They lead a 
most regular life, and smoking and the liberal use of alcoholic 
drink is absolutely forbidden. 

101. Alcohol is the enemy of muscle because it changes it into 
fat. When a muscle contains much fat it becomes weak and 
useless. Look at the drunkard and see how weak and flabby 
his muscles are. He may look big, but this is due to fat and 
not to muscle, and though he looks big he is bloated and puffed 
up ; he really is weak and tires easily. Nor is this all. The 
heart also is formed of muscle-tissue, and this becomes changed 
to fat in the drunkard ; then it cannot beat as strong as it 
should. It becomes weak, and the blood is no longer pumped 
into the arteries as it should be, and the entire body suffers. 



THE MUSCLES AND MOTION. 59 

Sometimes there is so much fat mixed with the muscle of the 
heart that its wall becomes thin, and it may even burst ; then 
instant death ensues. 



SYNOPSIS. 

Function of Muscle — Power of moving parts of skeleton. 
Description : 

1. Red masses commonly called flesh. 

2. Divisible into " fibres." 

3. Have the power of ' ' contracting " or shortening. 

4. There are three kinds : 

a. Voluntary — Under control of the will — muscles on 
outside of body. 

1. Appear striped under the microscope. 

2. End in tendons for attachment to bones. 

3. In contracting, become shorter, thicker, and 
harder. 

b. Involuntary — Not under control of the will — heart, 
walls of stomach and arteries, etc. 

1. Are not striped when seen under microscope. 

2. No tendons. 

c. Mixed — Consisting partly of voluntary, partly of in- 
voluntary fibres, such as muscles between the ribs. 

5. More or less fat between the fibres, between the different 
muscles, and covering them. 

6. Muscles usually occur in groups. 
Uses of Fat : 

1. To keep the body warm. 

2. To protect the body from pressure. 

3. To serve as a food. 

4. To improve the appearance of the body. 
The Way in which Muscles act : 

1. Become shorter. 

2. Become broader. 

3. Become thicker. 

4. Become harder. 

5. Bring together the parts to which attached. 



60 ANATOMY, PHYSIOLOGY, AND HYGIENE. 

6. Dependent upon the influence of the brain, spinal cord, 
and nerves. 

7. Ordinary muscular movements very complex. 
Number of Muscles — About three hundred on each side. 

Shape of Muscles — Varies greatly : Most frequently, long fleshy 
bundle ; flat, fan-shaped, square-shaped, circular, etc. 

Size of Muscles — Varies greatly ; smallest, a fraction of an inch 
(found in ear) ; largest, over two feet in length (extends from hip- 
bone to leg). 

A Few Important Muscles : 

1. Biceps — Front of arm — bends forearm upon arm. 

2. Triceps — Back of arm — straightens arm. 

3. Pectoralis — Muscle of chest — draws arm across chest. 

4. Diaphragm — Involuntary muscle separating abdomen from 
chest — muscle of breathing. 

5. Tendon of Achilles — Just above heel — lower end of a large 
muscle of leg — has received its name from story concerning 
Achilles. 

Care of Muscles : 

1. They suffer when general health is poor. 

2. They need regular and sufficient exercise. 

3. Children should have at least two or three hours' exercise 
every day, in the open air. 

4. Good forms of exercise — Bapid walking, moderate running, 
rowing, swimming, skating, bicycle-riding, horseback-riding, 
base-ball, foot-ball, tennis, croquet. 

5. Stop exercise when begin to feel tired. 

6. Avoid violent exercise. 

7. Effects of alcohol and tobacco on muscles : 

a. Enemies to the development of muscles. 

b. Alcohol changes muscle into fat (becomes weak and 
flabby). 

c. Alcohol changes heart into fat (becomes weak and 
does work poorly). 



THE MUSCLES AND MOTION. 61 



QUESTIONS. 

1. What use do we make of muscles? 2. What does muscle-tis- 
sue look like ? 3. What is it commonly called ? 4. W'hat are mus- 
cle-fibres ? 5. What are tendons ? 6. Of what use are tendons ? 
7. What can you say about the appearance and the strength of ten- 
dons ? 8. How does fat occur with muscle ? 9. What are the uses 
of fat in the body? 10. What proof is there that fat is used as 
nourishment by the blood? 11. Is there a larger proportion of fat 
in the baby or in the grown person ? 12. What three kinds of mus- 
cle are there ? 13. What is a voluntary muscle ? 14. Give an ex- 
ample ? 15. What is an involuntary muscle? 16. Give an ex- 
ample ? 17. Why is it necessary that some muscles shall be invol- 
untary ? 18. Give an example of the working of an involuntary 
muscle. 19. Do muscles ever belong to both classes? 20. Give 
an example. 21. What do we mean when we say a muscle " con- 
tracts ? " 22. How does the muscle change when it acts ? 23. Can 
the muscles contract of their own accord? 24. What causes the 
muscle to act? 25. What part does the brain take in the contrac- 
tion of muscles ? 26. What part do the nerves take in this ? 27. 
How can you prove that muscle itself cannot act without the influ- 
ence of the nerves ? 28. What two sets of muscles do we usually 
find together, and how does one set act toward the other ? 29. Give 
an example of two muscles which have just the opposite actions ? 
30. How are the different expressions of sorrow, joy, and the like 
produced in the face ? 31. What may result from continually hav- 
ing an ugly or a foolish expression in the face ? 32. How many 
muscles are there in the human body ? 33. Do muscles usually oc- 
cur singly or are they usually the same on one side of the body as 
on the other? 34. Mention some of the shapes of muscles. 35. 
How do muscles vary in size'? 36. Where is the Biceps muscle? 
37. Describe the Triceps muscle. 38. Describe the Diaphragm. 
39. Describe the chest-muscle, and give its other name. 40. Where 
is the Tendon of Achilles ? 41. From what circumstance did it re- 
ceive its name ? 42. How does the condition of our health affect 
the state of our muscles ? 43. What happens when we do not use 
our muscles? 44. What effect has exercise upon our muscles? 45. 
How much exercise should children have every day ? 46. Where 



62 ANATOMY. PHYSIOLOGY, AND HYGIENE. 

is the best place to take this exercise, in the open air or in-doors ? 
47. What is the best kind of exercise for children ? 48. Mention 
some of the good forms of exercise ? 49. What effect has exercise 
when it is continued too long ? 50. What effect has exercise which 
is too violent and heavy ? 51. What effects have alcohol and to- 
bacco upon the development of muscle ? 52. What do you mean 
by " alcoholic drinks ? " 53. What is meant by training ? 54. What 
is the effect of training ? 55. Why is alcohol injurious to'muscle ? 
56. What effect has alcohol upon the heart-muscle ? 



CHAPTEK V. 
FOOD AND DKINK. 

102. As we shall see further on, the different tissues of our 
bodies are being used up constantly. They are then replaced 
by materials taken from the blood. The blood receives the nu- 
tritious matters from our food and drink. Of course, our food 
has to be changed very much before the blood can absorb it to 
build up the different parts of the body. When we drink 
milk we say it is nourishing, and no doubt it is ; but the milk 
must become changed in the stomach and intestines, before it 
can enter the blood and circulate through the body, to replace 
used-up tissues. 

103. Food and Drink are Essential to Life.— Without 
food and drink we could not live ; they are necessary for life 
and growth. We often hear of people fasting for a long time ; 
it has happened that persons have lived for a few weeks with- 
out any food, but never without drink. If the body be deprived 
of both food and drink, death takes place, usually after several 
days. It is easy to see why this must be so. Even when we 
are as quiet as possible, the different tissues of our body are con- 
stantly changing, and are constantly being changed into material 
which is waste and must be cast off ; we must breathe, and our 
heart must act constantly, and both of these are muscular ac- 
tions and consume nutrition furnished by the blood. If the 
blood does not get a supply of this from our food and drink, it 
must take it from the tissues, and thus they would soon waste ; 
the person would die from weakness, because both blood and 
solid tissues would become changed so much that they would 
be unable to perform their functions. 



64 ANATOMY, PHYSIOLOGY, AND HYGIENE. 

104. Difference in the Food of Plants and of Animals. 

— The food of plants is quite different from that of animals ; it 
is very much simpler. Plants live upon air, the gases contained 
in the air, the moisture from the ground, and certain salts which 
are in the ground and which this moisture dissolves. These 
things are, of course, entirely too simple for animals to exist 
upon. Animals require something more. If you tried the ex- 
periment of feeding your pet dog upon nothing but water, air, 
and salts, you would find he would soon become very thin and 
weak, and would die from lack of food. 

105. Difference in the Food of Different Animals. — 
Some animals live almost entirely upon flesh, and are therefore 
called carnivorous — a long word, meaning that they devour 
flesh. The cat, the dog, the lion, and the tiger are examples 
of this class. 

106. Other animals exist upon vegetables, grass, grain, and 
the like ; they are called herbivorous — that is, " herb-devour- 
ing ; " of this class the cow, horse, and rabbit are examples. 

107. Man belongs to neither of these two classes ; he com- 
bines the two ; he requires both fleshy food and the other variety 
— vegetable — the kind produced by plants. 

108. Different Kinds of Food Required by Man. — It 
has just been stated that man requires fleshy food and vege- 
table food ; with these he must also have water and a certain 
amount of mineral salts. 

109. Fleshy Food. — By fleshy food is meant meat, whether 
from the ox, sheep, or other animal of this class, or from 
fishes. 

110. Vegetable Food. — This is the name given to the 
food which plants produce ; it contains starch, sugar, and other 
matters. One variety of this kind of food contains a large 
amount of starch, and is therefore called starchy food ; another 
name is farinaceous food. Examples of this kind are wheat, 
which furnishes the flour from which bread is made, corn, bar- 
ley, rice, oats, and the like. Hay also belongs to this class. 



FOOD AND DRINK. 



65 



Man could not, of course, eat hay, since his stomach is not ar- 
ranged so that he could digest it ; but the ox eats hay, and it 
is converted in his body into nutritious materials from which 
his flesh (beef) is formed, and the latter is then eaten by man. 

Ill; Starch. — It is important to thoroughly understand 
what starchy food is. You may have seen starch used for stif- 
fening linen. When used in this way, it is first mixed with 
water and then placed on the fire ; this causes it to swell up, 
and it becomes changed into a paste. Kaw starch is not suit- 




FiG. 33. — Starch Granules (from Potato) as Seen under the Microscope. 



able for food for man ; it must first be boiled ; this changes it 
so that it can be digested. All starchy food must first be boiled 
before it can be used as food. The cow and ox can eat hay 
and oats and can digest them ; but man would not think of 
taking oat-meal raw, but only after it had been boiled. The 
same applies to rice, farina, barley, and all other farinaceous 
food. There is no starch in fleshy food and there is none in 
animals ; it occurs only in plants. 

112. Starch is a white powder which has a strange, dry feel- 
ing. When looked at under the microscope, each grain of 



66 ANATOMY, PHYSIOLOGY, AND HYGIENE. 

the powder has a peculiar form and is marked by rings or 
lines (Fig. 33). 

113. Another form of vegetable food has a large quantity of 
sugar in it ; so that we are constantly taking in sugar with our 
food, and it forms nourishment. 

114. Then it is also necessary that we should eat green veg- 
etables, such as peas, spinach, string beans, salad, and the like. 
When deprived of these for airy length of time, the blood be- 
comes poor, and the body suffers. 

115. Fat and Fatty Food. — Fat or fatty food forms an 
essential part of our food. This is why we eat butter with our 
bread. The fat which we take in with our food may be vege- 
table, as for instance, certain nuts, or it is (more often) animal 
food in the form of butter from cows' milk and the fat around 
meat. In the body, starchy and sugary food is changed into fat ; 
this is why we say potatoes, bread, and the like are fattening. 

116. Water. — Water is even more necessary to life than is 
food. A person could live longer without food than without 
drink. The great drink is, of course, water. Three-fourths of 
the weight of the human body is water ; consequently water 
is an absolutely essential addition to our food. 

117. Tea and Coffee. — A good deal of the liquid which 
we drink consists of tea and coffee. Grown people are not usually 
harmed by tea or coffee if they do not take too much ; but both 
of these are injurious to children, and they are better off with- 
out them. Milk and water are the best drinks for children. 
Even grown people often make themselves nervous and trem- 
bling by drinking too much tea or coffee. Chocolate is like tea 
and coffee, but it also contains considerable fatty matter which 
is nutritious. Hence chocolate is more of a food, while tea and 
coffee are only stimulants — that is, they excite the system for 
the time and are luxuries. Children do not need any stimu- 
lants. 

118. Man must Combine all Forms of Food with 
Water. — Man is so constituted that he cannot exist upon any 



FOOD AND DRINK. 67 

one form of food alone. Meat is very nourishing, but a man 
could not exist on meat alone ; he would soon become thin and 
weak. He must have meat, fatty food, vegetable food, and 
water, all combined. 

Some of the Simplest Forms of Food.— We will now 
consider some of the different forms of food. 

119. Meat and Fish. — There are a great many different 
kinds of meat. Beef is used more than any of the others. 
There is always some fat mixed with the meat, even when we 
cannot trim off any more. Under this head also come chicken, 
turkey, and other fowl ; also the various birds. Fish is a very 
useful form of fleshy food, and is usually quite easily digested. 

120. Bread. — Bread is made from flour. In America, this 
is usually wheat ground up fine. The baker takes the flour 
and adds water and a little salt ; with these he makes the 
dough. He also adds yeast, and he will tell you he does this so 
as to make it raise, so that it will be light and easy of digestion. 
What does the yeast do ? When it is added to the dough it 
changes some of the starch so that a gas is given off. This 
gas escapes in bubbles but cannot get through the dough; 
when it tries to work its way out it puffs out the dough and 
makes it light and porous. Then this dough is put into the 
oven and baked ; a hard crust forms on the outside. Bread 
is often called "the staff of life," on account of its importance. 

121. Milk. — Most of the milk used by .,.*?&!>&&**. 
man is obtained from the cow ; but in some ^W&tBS3& 
countries milk is obtained from the goat and &° j§ ■% '.©•'. 
from the ass. Milk is one of the 7nost nutri- ?j8j W$B 
tious articles of food, and at the same time ' ? &^$$M^$$$i 
one of the most easily digested. Milk con- ^'^l&i^? ^ 
tains substances which are like all the differ- fk». 34.— a Drop of 

Milk Seen under the Mi- 

ent kinds of food which man requires — it croscope, showing the 
contains materials like those found in flesh, 
fat, and others which resemble those found in vegetable food, 
and it contains a large amount of water. Thus it has in it 



68 ANATOMY, PHYSIOLOGY, AND HYGIENE. 

everything that we require, and we could get along on milk with- 
out any other food. The baby thrives on milk alone for a long 
time, but after a while man longs for more variety in his food. 
The fatty part of the milk floats on top after the milk has 
stood for a time, when it can then be taken off; it is the 
cream. 

122. Butter is nothing but this cream pressed together. 
Cream consists of fat-globules (Fig. 34) ; when milk is churned, 
these fat-globules stick together, and in this way form a mass 
called butter. 

123. Milk from which the cream has been taken is called 
skimmed milk. If the milkman is dishonest, he may skim the 
milk and add water to it ; it then has a bluish tint, and is 
much less nourishing. 

124. If we add a little piece of the stomach of the calf to the 
milk, it causes one of its substances to separate and fall to the 
bottom ; if we take this and press it together, we have cheese. 

125. Eggs are obtained from the hen, and from other birds 
of this kind. They are very nutritious and are easily digested. 
The shell of the egg is lime. The contents of the egg consist 
of two parts — the white and the yellow. In the yellow or 
yolk of the egg is much fatty matter. Both portions of the egg- 
correspond to fleshy food. 

126. Variety in Food. — We could not eat the same kind 
of food every day, for we would soon get tired of it ; it is 
necessary to have different kinds of food. Certain things, how- 
ever, we seem never to tire of ; such are milk, butter, bread, 
beef. 

127. Proper Food. — If we want to remain healthy we 
must not eat improper food. Girls who eat too much candy, or 
too many pickles, usually have very little appetite for any 
proper food, and soon become pale and delicate. And boys 
who eat green apples before they are ripe, in summer, or un- 
ripe fruit of any kind, are sure to repent it ; they are apt to 
become sick, and to have great pain in the stomach. 



FOOD AND DRINK. 69 

128. Methods of Cooking. — Sometimes we eat our food 
raw ; as for instance, fruit. But usually we cook it, because 
it becomes more digestible and tastes better. In cooking, we 
may make use of a great many different plans. If it is meat, 
for instance, we may put it into water and boil it, or if we let it 
get a little thicker, we stew it. We may put it into the pan 
with some fat and fry it. By holding directly to the fire we 
broil it or roast it. Finally, by putting it into the oven, we 
bake it. Of all these different methods, boiling, stewing, and 
broiling, are most to be recommended, because they make the 
food most easy to digest. 

129. You must remember also to take food at regular times 
in the day. Usually three meals a day are enough. Never eat 
in a hurry, but chew your food well. Never eat so much at one 
meal that you feel heavy, full, and uncomfortable. 

130. Our Drinking-water. — Water is the great drink, and 
it is very necessary that it should be pure. Clear water is not 
always pure ; water may be very impure and still be very clear 
and transparent. And again, water may look a little cloudy, 
and yet be perfectly innocent and healthy. What makes some 
water unhealthy and injurious is poison dissolved from the soil. 
In cities where the water is brought from a distance in pipes, 
this poison is not apt to occur ; but in the country, where the 
water from wells is used, it is often present. In the country, 
very often no other water can be obtained except that from the 
well ; for convenience sake, the well is built near the house 
and the stable ; it is then very apt to be poisoned. Fig. 35 
illustrates very nicely the manner in which well-water may 
become poisoned. It is a good example of what occurs con- 
stantly in many places in the country where well-water is used 
without proper precautions having been taken to prevent poi- 
soning. 

131. An examination of the picture on p. 70 shows the follow- 
ing : To the right is the dwelling-house ; to the left is the stable 
with its manure-heap and pig-pen ; between these two is the 



70 ANATOMY, PHYSIOLOGY, AND HYGIENE. 

well. The surface of the ground is fairly level, and is sandy, 
and beneath this is gravel. The rain soaks into the porous 
ground, and in doing so dissolves poisonous matters from the 
manure-heap and the pig-pen ; after it has soaked into the 
ground it remains there, since below there is a layer of rock, 
which will not allow the water to pass. This poisoned water 
collects here, and then gradually enters the lower part of the 
well. When water is drawn from the well it will be easily 




Fig. 35. — A Section of a Dwelling, and its Accompaniments, as is often Found in the 
Country. The shading extending from the stable to the layer of rock at the bottom of the 
well, shows the course of the poisonous material from the stable, with its manure-heap and 
pig-pen, to the well. 

understood that it is partly the same water which has passed 
over and through the manure-heap and the dirt of the pig-pen 
before passing into the ground. The shading extending, on 
the figure, from the stable to the bottom of the well, shows the 
course which this poisoned water takes. Such water causes 
typhoid fever and other diseases in those who drink of it. It 
has often happened that a great many persons became sick in 
a village at the same time. When a great many persons be- 
come sick at the same time, and have the same disease, an 
epidemic is said to exist. Many epidemics have been found 



FOOD AND DRINK. 71 

to have been produced by the drinking of poisoned well- 
water. 

132. The water of a pure river should be preferred to that 
of a well. But sometimes we have no choice and must drink 
well-water. In this case we should see that the well is thirty 
feet or more from any inhabited building, and that no refuse 
or slops of any kind are allowed to soak into the ground. Such 
refuse should be kept in water-tight barrels and carted off 
regularly. If we are in doubt about whether the water is good 
or not, we may boil it thoroughly ; this destroys the poison, 
and then we are safe in drinking it. 

133. Water which has stood in leaden pipes all night dis- 
solves a little of the lead : hence when we use the water in the 
morning, we should allow it to run a few minutes before taking 
any. 

ALCOHOLIC DRINKS. 

134. These are called so because they contain alcohol. Let 
us now study what alcohol is, how it is made, its uses, and the 
injury and danger to man which it causes : 

135. Properties of Alcohol. — It is a clear, colorless liquid, 
resembling water in appearance, but lighter ; it has a pleasant 
smell ; it takes fire easily and burns ; its taste is very hot, and 
it burns the mouth. If we leave a little in a saucer, we soon 
find that it has disappeared into the air, and we say it has " evap- 
orated." It is very useful to us in many ways, for it dissolves 
oils and other things which water will not dissolve. It also 
extracts the good part of many roots, herbs, and barks ; in this 
way it is used a great deal by the druggist to make the dif- 
ferent medicines. So that alcohol is very useful in its way. 
It is only when misused as a drink that it causes such great 
harm. 

136. How Alcohol is Made. — If you take anything which 
contains much starch, whether it be corn, rye, potatoes, or 
anything of this sort, add yeast and water to it, and mix them, 



72 

you will soon find that the starch in these substances has turned 
into sugar. If you allow the mixture to stand longer and warm 
it slightly, little bubbles of gas will be seen escaping into the 
air ; we say it is fermenting. If anyone has seen sweet cider 
becoming sour, he will have noticed the bubbles of gas rising 
— this is an example of fermentation. 

137. At the same time that this gas is given off, we find 
the liquid is becoming less sweet than it was. After a time it 
will have lost all its sweetness and have the taste of alcohol. 
So that, first the starch has been changed into sugar, and then 
the sugar has become changed into alcohol. The alcohol re- 
mains in the liquid, while the gas, which is poisonous, escapes 
into the air. Sometimes a sugary liquid is taken at once, such 
as the juice of grapes from which wine is made ; in this case it 
is not necessary to change starch into sugar, for sugar is already 
present. 

138. If the preparation is to be an alcoholic drink it requires 
clearing and flavoring. If the drink is to be wine or beer this 
is done by allowing the liquid to stand, and pouring off the 
clear part, and straining it. If it is to be one of the liquors — 
whiskey, brandy, rum, and the like — the liquid is placed in a 
large vessel and is heated. The heat drives off the alcohol and 
some of the water and some flavoring matters ; these are col- 
lected and make liquor. 

139. If pure alcohol is wanted, it must be driven off by 
heat several times in succession, being collected again each 
time. 

140. Varieties of Alcoholic Drinks. — All alcoholic drinks 
are intoxicating ; but they differ in degree according to the 
amount of alcohol which each contains, and can be divided ac- 
cordingly into three classes : 

141. (1.) Beers and Ales usually contain from two to four per 
cent, of alcohol, and are made from barley, which is heated in 
the oven, so as to change the starch into sugar ; this makes it 
sweet, and it is then called malt. Afterward hops are added 



FOOD AND DRINK. 73 

to make the beer bitter. Ales and beers contain the least 
alcohol. 

142. (2.) Wines usually contain from eight to seventeen per 
cent, of alcohol ; they are made from the juice of grapes. 

143. (3.) Liquors contain about one-half alcohol ; the only 
difference in the various kinds is the flavor ; this depends 
upon the kind of grain used to furnish the alcohol, or upon 
whatever flavoring is added afterward. Whiskey is made 
from rye or from corn, brandy from grapes, rum from mo- 
lasses, gin is flavored with juniper, absinthe is flavored with 
wormwood. 

144. Effects of Alcohol and of Alcoholic Drinks.— Hav- 
ing studied what alcohol is and the nature of alcoholic drinks, 
the effects will now be considered. It would be untruthful to say 
that everyone who takes the least amount of alcoholic drink is 
seriously harmed by it ; for there are undoubtedly persons who 
can take a little drink without doing them any harm that we 
can notice. But it can certainly be said that, in general, it 
does them no good. Persons who can take any drink at all 
without any harm to themselves, take it only in small quantities 
and at meals. Alcohol, in the form of wines and liquors, is often 
prescribed by the doctor, and then it is a medicine, and is really 
useful. With this exception it can be said, and cannot be de- 
nied, that the world would be a thousand times better off if there 
was no such thing as alcoholic drink. If a prison be visited, and 
the convicts be asked about the crimes which brought them 
there, it is astonishing how many of them will blame drink. 
Many a man, who would otherwise have been good and useful, 
has been made a criminal by this poison. It may safely be 
said that there is no cause of crime so great and widespread as 
drink. 

145. Men do not become drunkards at once, but only after a 
while ; they commence with small quantities of drink, and the 
habit grows until they need larger and larger amounts to satisfy 
them. 



74 ANATOMY, PHYSIOLOGY, AND HYGIENE. 

146. Alcohol, in the form of drink, has the following effect 
upon the tissues : It irritates the stomach and constantly makes 
it red ; after a while, the wall of the stomach becomes tough, 
and is no longer suited for its work. When a large quantity 
of alcoholic drink is added to the food, it prevents it from being 
digested. It irritates the intestines. It makes the heart act too 
rapidly, and, after a while, also irregularly. It changes muscle- 
tissue into fat. It causes the liver to become enlarged and 
afterward to shrink. The blood-vessels become stiff and lose 
their elasticity. Upon the nose can be noticed how the veins of 
a drunkard stand out. 

147. There may be a feeling of warmth to the body after alco- 
holic drink has been taken, but this is only on the surface and 
soon leaves, and then the warmth of the body is lessened. This 
was shown very well in several North Pole expeditions, where 
men who drank freely of liquor were frozen before the rest. 
Persons who are exposed to great cold know from experience 
that they do better without alcoholic drink. 

148. Upon the brain alcohol acts by first exciting it, but this 
is soon followed by the optposite effect, and the person becomes 
dull and stupid. People who do much brain-work know that 
they are more active when they let wine, beer, and liquor alone. 
Alcohol excites the brain in one way, but it excites it so that 
the person becomes noisy, and often wishes to fight — hence it 
does not excite the most desirable function of the brain, name- 
ly, the intellect. 

149. The nerves are soon made unsteady, as is shown by the 
trembling hands and the unsteady walk of the drunkard. 

150. Finally, the moral view of the effects of alcoholic drink 
in large amount must be considered. One has only to think 
how shocking it is to see an intoxicated man stagger along the 
street, holding on to anything for support, with bad breath 
and dirty appearance, to be warned never to take alcoholic drink 
at all — certainly not before he is a full-grown man. One should 
also consider the large amount of money which is uselessly spent 



FOOD AND DKTNK. 75 

in liquor-saloons ; how many useful things could it buy, and 
how much good could be done with it. The time wasted in 
these rum-shops, which would otherwise be spent at home with 
the family, should also be considered. 



SYNOPSIS. 

Uses of Food and Drink : 

1. To support Life. 

2. To allow "growth. 

Differences in Food of Plants and of Animals : 

a. Food of Plants : 

1. Air. 

2. Gases in the air. 

3. Moisture from the ground. 

4. Salts from the ground. 

b. Food of Animals : 

1. Fleshy food (meat and fish). 

2. Fatty food. 

3. Starchy and sugary food, including green vegetables. 

4. Water (forms three-fourths weight of body) . 
Differences in Food of Different Animals : 

a. Carnivorous — Flesh-eating. 

b. Herbivorous — Eating vegetables, grass, grain, etc. 

c. Man— Mixed food. 
Drink : 

Water. 

Tea and coffee — Unnecessary for children — often harmful. 
Necessity for Combining all Forms of Food with Water. 
Some of the Simplest Forms of Food : 

Meat and Fish — Beef most common. 

Bread — Should be light and porous. 

Milk — Most nutritious — contains : 

a. Cream, making butter. 

b. A. material forming cheese. 
Eggs — Very nutritious. 

Methods of Cooking : 

1. Boiled — Placed in water and heated. 



76 ANATOMY, PHYSIOLOGY, AND HYGIENE. 

2. Stewed — Somewhat thicker than boiled. 

3. Broiled ) _ Exposed directly to fire. 

4. Boasted ) 

5. Baked — Placed in oven. 

6. Fried — Placed in pan with fat. 

Boiling, stewing, and broiling are most nutritious. 
Cautions Begarding Food : 

1. Variety. 

2. No improper food, such as much candy, unripe apples, 
etc. 

3. Begularity in meals. 

4. Plenty of time for meals. 

5. No overloading. 
Drinking-water : 

Should be pure. 
Clear water may not be pure. 
Healthy water may be a little cloudy. 
Danger of water from certain wells — 

Occurring through contamination from soil. 
Avoided by removal of well to distance of thirty feet or 
more from habitations, and removal of refuse without allow- 
ing it to poison the soil. 
Water from pure river preferable. 
Danger of poisoning from leaden pipes. 
Alcoholic Drinks : 

Properties of Alcohol : 

1. Clear and colorless liquid. 

2. Besembles water, but lighter. 

3. Pleasant odor. 

4. Takes fire readily and burns. 

5. Taste hot and burns mouth. 

6. Evaporates easily. 

7. May be useful in dissolving oils, etc. , and preparation 
of medicines. 

How Alcohol is Made : 

1. Addition of yeast and water to starchy or sugary sub- 
stance. 

2. Moderate heat. 

3. Boiling to drive off alcohol. 



food and drink. 77 

Varieties of Alcoholic drinks : 

1. Beers and Ales — Two to four per cent, alcohol ; made 
from malt. 

2. Wines — Eight to seventeen per cent, alcohol ; from 
grapes. 

3. Liquors — Fifty per cent, alcohol ; from grains, and 
variously flavored. 

Effects upon man : 

a. Very common cause of crime. 

b. Morally objectionable ; neglect family, etc. 

c. Injurious to body : 

1. Irritates and hardens stomach and interferes with 
digestion of food. 

2. Irritates intestines. 

3. Causes heart to beat too rapidly and irregularly. 

4. Changes muscle to fat. 

5. Enlarges, then contracts liver. 

6. Blood-vessels become stiff. 
6. Lessens bodily warm.th. 

8. Excites objectionable functions of brain and dulls 
the intellect. 

9. Weakens the nerves and causes trembling. 



QUESTIONS. 

1. Why must we take food and drink ? 2. What must happen to 
the food before it can be changed into our tissues ? 3. Describe the 
food upon which plants live. 4. Do all animals have the same kind 
of food ? 5. What difference is there between the kind of food 
which the cow takes and that which the dog eats? 6. What is 
meant by a "carnivorous'' animal? 7. What is meant by a "her- 
bivorous " animal ? 8. To which class does man belong ? 9. What 
is meant by "fleshy" food? 10. What is meant by "vegetable" 
food? 11. What is "farinaceous" food? 12. What is starch? 13. 
Do we find starch in animals ? 14 Why is it necessary to eat green 
vegetables? 15. Do we need fat in our food? 16. Can man exist 
on any one form of food alone ? 17. Why do we naturally eat butter 
with our bread? 18. How is bread prepared? 19. Why is yeast 



78 ANATOMY, PHYSIOLOGY, AND HYGIENE. 

added? 20. Could we exist on milk alone ? 21. Why? 22. What 
part of the milk does the cream represent ? 23. What is butter ? 
24. What is cheese? 25. What can you say about eggs as food? 
26. Could we eat the same kind of food every day ? 27. What fol- 
lows when we eat improper food? 28. Why is most of our food 
cooked? 29. Name some of the different plans of cooking food. 
30. What makes our drinking-water unhealthy ? 31. Explain how 
well-water is often poisoned. 32. How can you prevent poisoning 
of well-water ? 33. What is meant by alcoholic drink ? 34. What 
are the properties of alcohol? 35. How is alcohol made? 36. From 
what is the alcohol formed ? 37. What kinds of alcoholic drinks are 
there? 38. From what are beer and ale made? 39. About how 
much alcohol do they contain ? 40. From what is wine made ? 41. 
About how much alcohol do wines contain ? 42. From what are the 
different liquors made ? 43. About how much alcohol do they con- 
tain ? 44. What effect has alcoholic drink on the stomach ? 45. On 
the heart ? 46. On the liver ? 47. On the blood-vessels ? 48. On 
the heat of the body? 49. Upon the brain and nerves? 50. Why is 
alcoholic drink objectionable, even aside from its bad effects upon 
the health ? 51. What opinion would you have of a man whom you 
saw drunk? 52. What effect has the liquor-saloon upon a man's 
time and upon his purse ? 



CHAPTER VI. 
DIGESTION. 

151. The word digestion means the changing of the food by 
the organs in the abdomen, so as to liquefy it in order that the 
blood can take it up and make tissues out of it. Digestion 
commences in the mouth and ends in the large intestines ; if 
we commence from above, the following parts are met with : 
Mouth, throat, gullet, stomach, small intestine, pancreas, liver, 
large intestine. All of these except the pancreas and the 
liver, are hollow organs through which the food passes. All 
of these hollow organs taken together form the alimentary 
canal. Each of the organs of digestion will now be con- 
sidered : 

THE MOUTH. 

This is the commencement of the alimentary canal (Fig. 36) 
and is the cavity in which the food is chewed and mixed with 
saliva. 

152. The Teeth- — The chewing is done by means of the 
teeth ; these are supported by the jaws and occur in two rows, 
an upper and a lower. We do not have the same teeth when 
we are grown that we had when we were very small ; all the 
teeth which we have when very young children fall out ; they are 
only temporary, and they are called temporary or milk teeth. 
There are ten of these in each jaw, and thus twenty alto- 
gether. 

153. In the sixth year the temporary teeth begin to fall out, 



80 ANATOMY, PHYSIOLOGY, AND HYGIENE. 

and others commence to grow from the jaws to take their 
places. These are stronger than the first, and there are more 




Fig. 36.— Outline Sketch of the Organs of Digestion. 



of them. They are called the permanent teeth ; there are six- 
teen in each jaw. After the sixth year, the other permanent 



DIGESTION. 81 

teeth gradually replace the temporary ones which fall out. 
The last tooth to appear is that placed farthest back, called 
the wisdom-tooth ; this comes about the twenty-first year. 
154. Each tooth can be divided into the part which projects 




Fig. 3?.— The Tipper and Lower Jaws with the Permanent Teeth. 

into the mouth and which is called the crown, the part which 

sinks into the jaw, the fang or root, and the line between these 

two, called the neck. Teeth are composed of a very 

hard material, consisting very largely of lime, called 

dentine. They are hollow in the centre (Fig. 38) and 

this central space is filled up with a soft material 

called the pulp. On the surface of the crown is a 

covering of very hard material, formed principally 

of lime, called enamel. Each tooth is supplied with 

a small nerve which enters it through an opening 

in the end of the root. It is the exposure of section of one 

this nerve through the formation of cavities in Teeth? M ° ar 

the tooth which most often gives rise to toothache. 

155. Upon examining the teeth, we find they differ greatly 
in size and in shape. They are similar on the two sides of the 
mouth and are the same in the upper as in the lower jaw. In 




82 ANATOMY, PHYSIOLOGY, AND HYGIENE. 

Fig. 37 we see the teeth in position ; in Fig. 39 they are sep- 
arated, those on the right of the figure corresponding to 
the middle line, while those on the left are the back teeth. 
Commencing in the centre and proceeding toward each side 
(from right to left in Fig. 39) there are first two sharp-pointed 
teeth, having chisel-like edges ; these are the incisor teeth ; 
their sharp edges are intended to cut the food and to bite it 
into pieces. Next to these is a long, pointed tooth, called the 



Fang or Root. 





Crown. 

Neck. 

Fang or Root. 



Fig. 39.— The Permanent Teeth. Above are those of the upper jaw ; below, those of the 
lower jaw. The teeth of one side of the jaw only are represented. The two teeth to the 
right are incisors. The long tooth next to these is the canine tooth. The two following 
ones are bicuspids. The last three (to the left) are molars. 



canine, also known as the eye-tooth ; in the dog and cat, and ani- 
mals of this type, it is of great length and sharpness, and is 
used for tearing meat. Next to the canine are two broader 
teeth having two sharp points each ; they are known as the bi- 
cuspid teeth. Still further back there are three large, broad 
teeth ; the surface of their crowns is very uneven, but they are 
very strong ; they are the molars and serve to grind up the 
food into small particles. 

156. The teeth are intended to chew the food so that it is in 
small enough particles to be received and digested by the 



DIGESTION". 83 

stomach. Hasty eating results in the swallowing of food which 
has not been chewed sufficiently, giving rise to indigestion, 
pain in the stomach, and, if continued, dyspepsia (which means 
difficult digestion). 

157. Care of the Teeth. — Teeth are natural ornaments when 
nice and healthy ; they are very disfiguring when dirty or de- 
cayed. Teeth should be brushed every morning upon rising, 
and every night before retiring ; they should be kept clean at 
all times. If particles of food lodge between the teeth, they 
should be removed with toothpicks of wood or quill — never 
with pins, needles, or metallic points. Teeth are apt to decay 
and cavities form, if the general health becomes poor, also if 
much improper food be taken ; by improper food is meant, a 
great many pickles, much candy and cake, and food which is 
difficult to digest or too acid. Teeth should not be used to 
crack nuts with, nor for anything but chewing. When cavities 
have formed in the teeth, the dentist fills them with gold or 
silver foil so as to prevent them from decaying more. 

158. The vulgar habit of chewing tobacco discolors the 
teeth ; smoking also does this, unless great care be taken to 
clean them often. 

THE SALIVARY GLANDS. 

159. We give the name glands to certain bodies, usually 
small and round, in which fluid is formed, to be used in vari- 
ous ways. For instance, around the mouth there are many 
such glands, and they form the saliva — that is, the fluid which 
constantly keeps the mouth wet, and also moistens our food ; 
hence, these glands around the mouth are called the salivary 
glands. There are a great many of them, but most of them 
are very small. Three, however, are larger and are worth 
mentioning. 

160. The largest is placed in front of the lower end of the 
ear, around the joint of the lower jaw, and has a small tube 



84 

leading to the mouth ; it is called the parotid gland. Another 
is placed just below the tongue, and is therefore called the sub- 
lingual gland. A third is found underneath the chin on each 
side, and is called the submaxillary gland. 

161. These glands pour some of the saliva into the mouth 
all the time, but they are especially active when we use the 
jaws either in speaking or in eating ; if it were not for this 
fluid, the saliva, the mouth would soon feel dry after talking a 
little. In eating anything dry, such as a cracker, we notice 
that enough fluid forms in the mouth to moisten it thoroughly 
and thus enable us to swallow the mass ; it would be difficult 
to swallow if it were dry. "When the saliva is mixed well with 
the food, the stomach can act on the food at once and digest it 
easier. This is another reason why we should chew our food 
well. 

162. There is still another reason : A small part of starchy 
food is digested by the saliva before it reaches the stomach ; 
this is an aid to the stomach in its work of digestion. 

163. Effects of Chewing Gum. — The habit of constantly 
chewing gum not only looks bad, but by making the saliva 
flow in large quantity all the time it makes it thin and watery ; 
such saliva is apt to be inefficient in the proper performance of 
its work during meals. This habit is, therefore, not only vul- 
gar, but unhealthy. 

THE THROAT. 

164. This is the wide part of the mouth behind, into which 
the food passes after it has been thoroughly chewed and when 
we swallow it. While we are swallowing, it passes into the 
throat. Once swallowed, the food passes into the canal leading 
to the stomach, the gullet, or oesophagus, then it continues its 
way without our knowledge or will (Fig. 36). 



DIGESTION. 85 



THE TONGUE. 

165. This is also- one of the organs of digestion, since by its 
movement the food is rolled around in the mouth and mixed 
thoroughly with saliva. The tongue also assists in swallowing. 
This organ will be described under the special senses, as it is 
also the organ of taste. 

THE GULLET, OR (ESOPHAGUS. 

166. This is a long tube (Fig. 36) which connects the mouth 
and throat with the stomach. Its walls are formed of rings of 
muscle-tissue. When these rings contract, the food is forced 
downward until it reaches the stomach. 



THE STOMACH. 

167. The Stomach is a sort of bag about a foot long, placed 
in the upper part of the abdomen, just below the diaphragm. 
The latter, as has already been mentioned, is the sheet of mus- 
cle-tissue separating the abdomen from the cnest. The stom- 
ach commences near the middle of the body, and then extends 
over toward the right. There are two openings into the stom- 
ach. One is for the entrance of food, which is carried by the 
gullet from the mouth ; in order to reach the stomach, the gul- 
let must, of course, pass through the diaphragm. The other 
opening of the stomach is at the farther end, and allows the food 
to pass on into the intestines after the stomach has done its 
work. Around this opening is a sort of narrowing which re- 
mains closed until the food is ready to be sent to the intes- 
tines. This narrowing is produced by a thickening of the tissue 
at this point, and is called the pylorus. 

168. The wall of the stomach is not very thick, but it is very 
strong. On the outside there is a smooth, shining coat, which 
is merely part of a membrane lining the whole inside of the 



86 



ANATOMY, PHYSIOLOGY, AND HYGIENE. 



abdomen and the organs in it. This membrane is known as 
the peritoneum. On the inside there is a soft, velvety coat, 




Pig. 40. — The Stomach, Showing the Layer of Muscle-tissue by which it Contracts and 
Propels the Food. 



called the mucous layer (Fig. 41). We often meet with the 
term mucous membrane in anatomy ; it refers to a soft, smooth, 




FlG. 41.— The Inner Surface of the Stomach, Showing the Mucous Layer Arranged in Fold? 



DIGESTION. 



87 



velvety membrane which is called mucous because it forms and 
is kept moist by a watery, slippery fluid called m ucus ; the 
fluid from the mouth between meals and the fluid which runs 
from the nose are examples of mucus. In between these two 
surfaces, the mucous and the peritoneum, is a layer of muscle- 
tissue which forms the main part of the thickness of the stom- 
ach (Fig. 40). 

169. Gastric Juice. — The inner, or mucous, layer of the 
stomach is arranged in a series of folds which are especially 
marked when the stomach is empty. It is usually of a piuk or 
of a grayish color, but the color and appearance differ greatly 
according to the time at which we examine it — whether the 
stomach contains food or is empty. When food reaches the 
stomach, it excites it, and the soft 
lining then begins to swell, and be- 
comes reddened. We also notice in 
this mucous layer, when looked at 
under the microscope, a large num- 
ber of small dots or openings. 
When food is in the stomach, we 
can see drops of fluid escape from 
these dot-like openings ; this fluid 
is called the gastric juice. 

170. The Gastric Tubules 
and the Gastric Juice. — The 
gastric juice is a very important 
fluid ; it is only found in the 
stomach when food is present ; 
the presence of food causes it to 
flow. Of course the lining of the 
stomach is never dry, but it is 
moistened only with mucus, except 
when excited by food ; then gastric juice begins to flow. 
Upon examining this internal layer of the stomach under the 
microscope, we find thousands of small tubes, lined by little 




Fig. 42.— A Section of the Lining 
Membrane of the Stomach, Very 
Highly Magnified, Showing the Gas- 
tric Tubules in Position. 



88 ANATOMY, PHYSIOLOGY, AND HYGIENE. 



oblong bodies, which we call cells (Figs. 42 and 43), These 
cells pour the gastric juice into the small tubes, and from these 
it passes into the stomach and is mixed with the food. But, it 
may be asked, where do these cells take the gastric juice from? 
They get it from the blood. There are tiny blood-vessels every- 
where, and certain portions of the blood pass through the walls 
of the blood-vessels into the cells, and are mixed there 
with other substances ; in this way the gastric juice 
results. 

171. Pepsin. — The substance in the gastric juice 
which enables it to digest fleshy food is called pepsin. 

172. Function of the Gastric Juice. — The 
work of the gastric juice is to digest food. But it 
does not digest every sort of food. It will digest only 
fleshy food. Vegetable food is digested elsewhere — 
a little by the saliva, but chiefly in the small intes- 
tine. Fat, also, remains undigested in the stomach, 
and passes on to be digested in the small intestine. 

173. (1.) Uses of the Stomach.— One of the 
uses we have just stated, namely, to digest the fleshy 
part of the food. 

174. (2.) The second use of the stomach is to be a 
sort of storehouse for the food. It takes between two 

Tubuil the an ^ three hours to digest an ordinary meal ; if there 
were no large bag in which the food could be kept 
until digested we would have to keep eating little by little all 
the time. The large size of the stomach also allows the gastric 
juice to be mixed quickly and thoroughly with the food, and 
thus digestion takes place quicker than it otherwise would. 

175. (3.) Still another use of the stomach is to churn the 
food, and to roll it about so that it is ground into the smallest 
particles and is well-mixed with the gastric juice. One of the 
coats of the stomach consists of muscle-tissue, and it is this 
coat which causes these motions of the stomach. Besides, the 
lining of the stomach has a large number of raised lines or 



DIGESTION. 89 

ridges (Fig 41) ; these projections make the breaking-up of 
the food still easier. 

176. Man has but one stomach. Some of the lower animals, 
such as the ox and cow, have four stomachs. Such animals 
swallow grass and hay without thoroughly chewing them. 
Afterward this food passes up into the mouth again. It is 
then chewed over again, swallowed, and after passing through 
the series of stomachs, it is finally digested. 

177. Effect of Tobacco on the Stomach. — When a per- 
son smokes tobacco for the first time, it makes him sick at his 
stomach. He may get used to the tobacco after a while ; but 
still, if he smokes too much, he has the same disagreeable sen- 
sation. Many persons make their stomachs weak and delicate, 
and spoil their appetites, by smoking and chewing tobacco. 

178. Effect of Alcohol on the Stomach.— Alcohol red- 
dens the lining of the stomach and irritates it. After a while 
it hardens it, thins it, and renders it unfit to digest the food 
properly. 

179. The Discovery of How the Stomach Acts. — 
Many years ago, a Canadian named St. Martin was shot in the 
abdomen ; he recovered with a permanent opening leading 
from the outside into the stomach, through which the doctors 
could watch and see what happened after eating. They found 
that ordinarily it took the stomach from two to three hours to 
finish its work, and to discharge what it could not digest into 
the small intestine or bowel. This man lived a great many 
years with the curious opening, and was quite strong and 
healthy. 

180. Certain kinds of food require a longer time than other 
kinds for digestion, and hence we call them heavy, or indigest- 
ible ; other food is digested very quickly, and is called light, or 
easily digestible. As examples of heavy food may be men- 
tioned, hard-boiled eggs, pies, cheese, etc. As examples of 
easily digested food, there are milk, soft-boiled eggs, toast, 
broiled steak, etc. 



90 ANATOMY, PHYSIOLOGY, AND HYGIENE. 



THE BOWELS OR INTESTINES. 

181. These consist of a long, hollow tube, of about twenty- 
five feet, commencing at the stomach (Fig. 36). Where stom- 
ach and intestines meet is a narrow opening, which is closed, 
except when the stomach has digested what it can of the food, 
and wishes to empty what is left into the intestines. 

182. This narrowing is called, as has already been mentioned, 
the pylorus, meaning gatekeeper, and it will be seen that it is 
well-named, for it guards the outlet of the stomach. The rem- 
nants of food which the stomach refuses to digest pass this 
point in the form of a soft, creamy mass. 



SUBDIVISIONS OF THE INTESTINES. 

183. The intestines can be divided into three parts : the first 
part, which is next to the stomach, is called the duodenum, a 
long word, which was given to it in olden times because it is 
about as long as twelve fingers put side by side — so that this 
part of the bowel is quite short. The second part is very long 
— twenty feet — and forms the principal part of the bowels ; it is 
called the small intestine, and the word small is used because it 
is narrower than the rest. The remainder of the bowels (about 
five feet long) is the last portion, and it is called the large intes- 
tine, because it is wider than the rest. 

184. The intestines are twenty-five feet long. In order that 
they may be contained in the abdomen they are folded together 
many times around a sort of stem which is attached to the back- 
bone. In this way they can move around somewhat, and yet 
they are kept in place by being held to the backbone. It will 
be seen later why it is necessary that they should be allowed a 
certain amount of motion so as to cause the remains of the food 
to move on. 

185. The intestines have the same coats as the stomach. 



DIGESTION. 91 

There is on the outside a smooth, shining coat (the peri- 
toneum). On the inside is a soft, smooth, velvety coat (the 
mucous coat). Between these two there is a coat formed of 
muscle-fibres, which run around the intestine in circles ; there 
is much less muscle-tissue around the intestine than in the 
walls of the stomach. 

186. The Peritoneum. — The shining outside coat of the 
intestine is very important, and is formed of the same layer of 
tissue that lines the whole abdomen. The whole inside of the 
abdomen and the outside of all the organs in it are covered 
with this smooth sheet of tissue which we call the peritoneum. 
This covering is necessary so that the organs can move one 
upon the other without pain, injury, or friction. The smooth 
surface is always kept moist by fluid. 

187. Motion of the Intestines. — The intestines are never 
quiet. They are in motion all the time. This motion resem- 
bles that of a worm — slow, gradual, and creeping. It is ac- 
complished by means of the muscle-fibres which exist in the 
walls. The object of this motion is to propel the food along so 
as to spread it out and hasten the absorption of the liquid and 
nourishing portions of the digested food. 

188. Projections on the Inner Surface of the Intes- 
tines. — The inner surface of the intestines looks pinkish and 
is velvety. It has a large number of valves or ridges (Fig. 44) 
running across it ; these prevent the food from passing along 
too rapidly, so that all the nutritious portions may be absorbed. 
Besides these projections we find that the velvety appearance 
is due to the presence of millions of other very small projections 
(Fig. 45), which resemble hairs in shape but are soft, and when 
looked at with the microscope are found covered with cells. 
We also find, when we examine the mucous lining of the in- 
testines, a great many small tubes similar to those found in 
the stomach. 

189. The Work of the Intestines.— The intestines finish 
the digestion of the food. They also afford a lengthy surface 



92 



ANATOMY, PHYSIOLOGY, AND HYGIENE. 



over which the liquid and digested nutritious parts of the food 
can pass and be absorbed by the blood, which then brings them 
to different parts of the body. We found that a small part of 
starchy food is digested by the saliva and that the stomach di- 
gests the fleshy portions of the food. The intestines digest the 
rest, namely : (1) the larger part of starchy food which is not 
affected by the saliva, (2) the entire fatty portion of the food, 
and (3) any remnants of fleshy food which the stomach may 
have failed to act upon. 

190. Starch cannot be taken up by the blood until it has 











MMmm 



Fig. 44.— The Inner Surface of the Small 
Intestine, Showing the Valves or Ridges. 



Pig. 45.— The Small Hair-like Projections 
from the Inner Surface of the Intestine. 
(Very highly magnified.) 



become changed into sugar. Fat must also first become al- 
tered by fluids in the intestines before the blood can absorb 
it. 

191. Openings into the Small Intestine.— The main 
work of the intestine takes place at the upper part near the 
stomach. Just below the stomach we find two openings leading 
into the part of the intestine known as the duodenum. One 
of these openings is the canal from the liver and the gall-bladder, 



DIGESTION. 93 

the other is the canal from the pancreas. Previous to discussing 
digestion in general, the organs furnishing these two canals 
will be considered. 

THE LIVER AND THE GALL-BLADDER. 




Fig. 46.— The Liver, Upper Surface. 



192. The liver (Figs. 36, 46, and 47) is a large organ of a 
brownish color, placed in the upper part of the abdomen, to the 
right of the stomach. It is just below the diaphragm and the 




Fig. 47.— The Liver, Under Surface ; Below, the Gall-bladder is Seen. 

lower ribs, which cover it in front and above by forming an arch 
over it. The liver is very heavy ; it is smooth on the outside, 



94 



ANATOMY, PHYSIOLOGY, AND HYGIENE. 



being covered by the same smooth membrane which covers all 
the organs of the abdomen, the peritoneum. It is subdivided 
into five sections called " lobes " by deep lines. 

193. Uses of the Liver. — The liver is a very important 
organ. Its uses are 

(1.) To make the bile. 

(2.) To purify the blood which passes through it. 
(3.) To add a certain nourishing body to the blood which 
passes through it. 
194 The Gall-bladder and Bile.— If we look at the liver 
under the microscope, so that it is very much enlarged, we will 

see that it is formed entirely of 
small cells, like cubes, packed one 
against the other (Fig. 48). These 
cells manufacture the bile and it 
is then collected by small tubes. 
Along the lower edge of the liver 
a bag about the size of an egg 
will be seen ; it is called the " gall- 
bladder " (Figs. 36 and 47) and the 
tubes which collect the bile empty 
into it. This bag keeps the bile un- 
til it is wanted. The liver is making bile all the time and yet 
the intestines do not need it except when food is present ; 
hence there must be such a storehouse. 

195. Action of the Bile. — After the stomach has finished 
its work and the changed food has passed into the intestine, 
the bile which has been stored up in the gall-bladder is allowed 
to escape into the intestine by a small tube leading to one of 
the two openings in the duodenum already described. The 
bile is of a green or brown color. We do not know what the 
bile does to the food exactly ; but we are certain that bile 
must be mixed with it, for if absent the person cannot live 
very long. Sometimes bile gets into the blood and then causes 
a yellow color of the skin, which we call jaundice. 




Fig. 



48. — The Liver-cells, 
Highly Magnified. 



Very 



DIGESTION. 95 

196. There is a great deal of blood passing through the 
liver ; it is purified while it passes through, and certain un- 
healthy parts are removed. 

197. After a meal there would be a great deal of nourishing 
matter thrown into the blood all at once ; this would soon be 
used up and then there would be no more until the next meal. 
In order to prevent this, the liver takes care of a large amount 
of sugar and keeps it stored up, and then gradually lets it re- 
turn little by little into the blood. 

198. The Unhealthy Liver. — Many sicknesses are caused 
by changes in the liver. If we eat too much at a time, or eat 
food which is too rich, such as a good many wealthy people do, 
the liver becomes diseased and does not remove the impurities 
of the blood as it should ; these then remain in the blood and 
give much trouble. Perhaps some of you have seen old gen- 
tlemen limp along with the aid of a cane. They cannot walk 
well because their big toes are swollen and sore ; they often 
have gout from too rich food, too much wine, and too little exer- 
cise. 

199. The Drunkard's Liver. — The liver suffers very 
much as the result of large quantities of alcoholic drink. It 
sometimes grows too large, and sometimes gets too small. 
The blood cannot flow through it as it should ; the liver can- 
not do its work properly. Thus the entire body suffers as the 
result of this, and the most serious symptoms trouble the un- 
fortunate man who leads the life of a drunkard. 

THE PANCREAS. 

200. This is one of the organs of digestion (Fig. 36). The 
pancreas of the calf is sold by the butcher as sweetbread. This 
organ is not large, but is very important. It is placed just be- 
low the stomach. Its work is to prepare a fluid called the 
pancreatic juice. This is made by cells, just as in the liver ; 
small tubes then collect the fluid and open into one large 



96 ANATOMY, PHYSIOLOGY, AND HYGIENE. 

tube which empties into the commencement of the small in- 
testine. 

201. Uses of the Pancreatic Juice.— The pancreatic 
juice digests all parts of the food which are left after the saliva 
and the gastric juice of the stomach have acted upon them. 
Thus it digests fat and starch ; and it will also digest any of 
the fleshy food which the stomach has neglected to change. It 
is consequently a very important fluid. 

ABSORPTION. 

202. All the fluids of digestion just described — the saliva, 
gastric juice, and pancreatic juice — simply change the chewed 
food, so that the blood can take it up or absorb it as nourish- 
ment ; this action of these fluids is called digestion. There 
still remains to be seen how the blood absorbs this nourish- 
ment, and what it does with it. 

203. If we look at one of the smallest blood-vessels (Fig. 53) 
it will be found that the walls consist of the very thinnest 
membrane, and that this allows fluids to pass through quite 
readily. In the lining of the stomach and intestines we find a 
great many of these tiny blood-vessels ; as the food reaches 
these places and has become digested, it passes into the blood- 
vessels and is carried with the blood to the different parts of 
the body, to be used in forming and building up tissues which 
are constantly being consumed. 

204. Lacteal s. — Besides passing directly into the blood- 
vessels, the digested food also passes into certain other tubes 
of very small size, like blood-vessels, except that they do not 
contain blood. These small tubes are called lacteals, from a 
Latin word meaning milk, because the nourishing fluid which 
they carry and afterward add to the blood looks white, like 
milk, during digestion. These lacteals finally empty into large 
veins at the lower part of the neck (Fig. 62). 



DIGESTION. 97 



HABITS WHICH ARE INJURIOUS TO PROPER DIGESTION. 

205. (1.) Eating too quickly. When the food is eaten too 
quickly it cannot be chewed properly, and the result is that it 
is swallowed in large pieces. The stomach has great difficulty 
in digesting these large pieces and thus indigestion and dyspep- 
sia result if the practice be continued. 

206. (2.) Eating too much at a time. This gives the organs 
of digestion too much work to do, and on this account all the 
food cannot be digested. We should not continue to eat until 
we feel heavy and uncomfortable, but should stop before we 
feel this way. 

207. (3.) Eating too many sweets and sours. While a pickle 
occasionally at meals, or candy and cake now and then, will do 
no harm, if these things are taken constantly they are injurious, 
because they destroy the appetite for nourishing food. 

208. (4.) Chewing gum gives the salivary glands too much 
work, and thus the saliva soon becomes too thin and does not 
act as it should. 

209. (5.) A large amount of ice-water. A little ice-water, taken 
slowly, will do no harm, whether during meals or at other times ; 
but to drink down a gobletful rapidly when the body is heated 
is very unhealthy ; it chills the stomach and delays digestion. 

210. (6.) Violent exercise immediately after a meal. This 
should not be indulged in, for at that time the stomach needs 
all the blood it can get. Violent exercise would drive all the 
blood to the muscles. 

211. (7.) Severe brain work is not good directly after meals. 

212. (8.) Bathing should not be indulged in until two hours 
after an ordinary meal. 

213. (9.) Excitement of any kind, such as good news or bad 
news just before a meal usually takes away our appetite. If 
we eat, nevertheless, the food will not be digested, or only very 
imperfectly. 

7 



98 ANATOMY, PHYSIOLOGY, AND HYGIENE. 

214. (10.) Alcoholic drink makes the food less digestible, es- 
pecially if it be strong drink ; it also irritates the stomach 
needlessly. 

215. (11.) Smoking will destroy the appetite and interfere 
with digestion in many persons. 

THE SPLEEN. 

216. The spleen (Fig. 36) is not one of the organs of diges- 
tion ; but its description will be given at this place, because it 
is placed in the abdomen. It is a round, flattened organ, solid, 
and contains a great deal of blood. It is found on the left 
side of the abdomen just underneath the lower ribs. Its use 
is not exactly known ; lately, however, it has been thought 
to take part in supplying the globules to the blood. It be- 
comes enlarged in all malarial diseases, and then sometimes 
reaches an enormous size. 

SYNOPSIS. 

Digestion — The changing of the food and its liquefaction, so that 
the blood can absorb it. 

Organs of Digestion : Month. 
Teeth. 
Tongue. 
Throat. 
Gullet. 
Stomach. 

c Duodenum. 
Intestines. < Small Intestine. 
( Large Intestine. 
Liver. 
Pancreas. 
Mouth — To chew the food and mix it with saliva. 

a Tongue — Assists in mixing food with saliva and in 
swallowing. 
b. Teeth: 

j j a. Temporary or milk teeth — ten in each jaw. 
I b. Permanent — sixteen in each jaw. 



DIGESTION. 99 

Four incisors. 
Two canine. 
Four bicuspid. 
Six molars. 

2. Divisible into 

r Crown. 

a. Parts : •< Neck. 

( Boot. 
r Enamel. 

b. Structure : ■< Dentine. 

( Pulp (cavity). 

3. Care of — Should be kept clean. 

Brushing. 
Toothpicks. 
Improper use. 
Tobacco, 
c. Salivary Glands : 

1. Location : 

(1.) Parotid — In front and below ear. 
(2.) Sublingual — Below tongue. 
(3.) Submaxillary — Below jaw. 

2. Saliva. 

(1.) Produced during chewing. 
(2.) Moistens food. 
(3.) Digests a part of starchy food. 
(4.) Keeps mouth moist. 
(5.) Watery, clear fluid. 
(6.) Necessity for thorough chewing. 
(7.) Effect of chewing gum. 
Throat : 

1. Between mouth and gullet. 

2. Concerned in swallowing. 
Tongue : 

1. Mixes food with saliva. 

2. Assists in swallowing. 
Gullet or (Esophagus : 

1. Connects throat and stomach. 

2. Formed of rings of muscle -tissue. 

3. These force food into stomach. 



100 ANATOMY, PHYSIOLOGY, AND HYGIENE. 

Stomach : 

1. Position — Upper part of abdomen, just below dia- 
phragm. 

2. Openings— One for entrance of food ; other (pylorus) 
into intestines. 

3. Coats : 

(1.) Outer — Peritoneum. 
(2.) Middle— Muscle-tissue. 
(3.) Inner — Mucous membrane. 

4. Uses : 

(1.) To secrete gastric juice, which — 

a. Is formed during digestion. 

b. Digests fleshy food. 

c. Contains pepsin. 

d. Is formed in the gastric tubules. 
(2.) A storehouse for the food. 

(3. ) To churn the food and break it into small particles. 

5. Effects of alcohol and tobacco — Alcohol irritates, to- 
bacco sickens. 

6. Discovery of action — St. Martin ; opening in stomach. 

7. Digestibility — Heavy and light food. 
The Intestines : 

1. Connection with stomach — By pylorus. 

2. Subdivisions: 

a. Duodenum. 

b. Small intestine. 

c. Large intestine. 

3. Length — Twenty -five feet. 

4. Attachment — To backbone. 

5. Coats — Same as stomach : 

a. Outer or peritoneum. 

b. Middle or muscle tissue. 

c. Inner or mucous membrane. 

6. Motion — To propel food and digested fluids. 

7. Projections from inner surface : 

a. Valves or ridges. 

b. Hair-like projections. 

8. Function : 

a. Digest starchy food. 



DIGESTION. 101 

b. Digest fatty food. 

c. Digest remnants of fleshy food. 
9. Openings : 

a. From liver and gall-bladder. 

b. From pancreas. 
The Liver and Gall-bladder : 

1. Position — Upper part of abdomen, to right of stom- 
ach. 

2. Description — Large, solid, brownish, subdivided into 
five sections or lobes. 

3. Uses: 

a. To make bile. 

&. To purify the blood. 

c. To add nourishment to the blood ; storehouse. 

4. Bile : 

a. Color — Greenish or brownish. 

b. Action — Not exactly known. 

c. If gets into blood — Jaundice. 

5. Unhealthy Liver — From too rich food, too much wine, 
too little exercise, gout. 

6. Drunkard's Liver — Too large or too small. 
The Pancreas : 

1. Position — Just below stomach. 

2. Use — To form pancreatic juice, which — 

a. Digests fat. 

b. Digests starch. 

c. Digests remains of fleshy food. 

Absorption — The taking up of digested food in fluid form by the 
blood and lymphatics : 

1. By blood-vessels. 

2. By lymphatic vessels. 

3. By lacteals. 

Habits Injurious to Proper Digestion : 

1. Eating too quickly. 

2. Eating too much at a time. 

3. Eating too many sweets and sours. 

4. Chewing gum. 

5. Ice-water in large amount. 

6. Violent exercise immediately after meals. 



102 ANATOMY, PHYSIOLOGY, AND HYGIENE. 

7. Severe brain-work immediately after meals. 

8. Bathing after meals. 

9. Excitement before, during, or after meals. 

10. Alcoholic drink. 

11. Smoking or chewing tobacco. 
The Spleen : 

1. Description — Bound, flattened, solid organ full of blood. 

2. Position — Left side of abdomen, underneath lower ribs. 

3. Use — Probably to supply globules to the blood. 

4. Enlarged — In malarial diseases. 

QUESTIONS. 

1. What is meant by the word " digestion" ? 2. Name the organs 
of digestion ? 3. What are the teeth for ? 4. What are the tem- 
porary teeth ? 5. When do we begin to have our permanent teeth ? 
6. How many permanent teeth are there in each jaw ? 7. What are 
the parts of each tooth? 8. Are the teeth solid or hollow? 9. 
What names are given to the different teeth ? 10. Which are the 
incisor teeth, what is their shape and their use ? 11. What is pecu- 
liar about the canine tooth? 12. What about the bicuspid teeth ? 
13. What about the molar teeth ? 14. Of which three parts does 
each tooth consist ? 15. What is the proper way of taking care of 
the teeth ? 16. What effect has tobacco on the teeth ? 17. What 
are the salivary glands ? 18. Where are they found ? 19. What is 
their use ? 20. What is saliva ? 21. What are the uses of saliva ? 
22. What are the effects of chewing gum upon the saliva? 23. 
Where is the gullet ? 24. Where does it lead to ? 25. What is the 
shape of the stomach ? 26. Where is it placed? 27. What open- 
ings are there in the stomach ? 28. What coats are there to the 
wall of the stomach ? 29. How does the inside of the stomach look 
when it is empty ? 30. How does it look when food enters the 
stomach? 31. What is the gastric juice? 32. How is the gastric 
juice made ? 33. Of what use is the gastric juice ? 34. When does 
the gastric juice flow ? 35. What kind of food is digested by the 
gastric juice? 36. What is pepsin ? 37. What are the three uses 
of the stomach ? 38. Have any animals more than one stomach ? 
39. How does the ox digest hay ? 40. What effect have tobacco 
and alcohol upon the stomach ? 41. How was the way in which the 



DIGESTION. 103 

stomach acts in man discovered? 42. What is meant by "heavy" 
food ? 43. What is meant by ' ' light " food ? 44. Give examples 
of each. 45. What is another name for the bowels? 46. How long 
are the bowels ? 47. How do the bowels connect with the stomach ? 
48. What kinds of food are still undigested when they leave the 
stomach? 49. What is the " pylorus ? " 50. Into what three parts 
can the intestines be divided ? 51. What is the name given to each 
part? 52. How are the intestines arranged so that they can all find 
room in the abdomen ? 53. To what are the intestines attached ? 
54. What coats have the intestines ? 55. What can you say about 
the outside shining coat of the intestines ? 56. What is the "peri- 
toneum," and what does it cover? 57. Tell about the lining of the 
intestines. 58. What is the work of the intestines ? 59. What 
kinds of food are digested by the small intestine ? 60. In what part 
of the small intestine does most of the work take place ? 61. What 
openings are there into the first part of the small intestine ? 62. 
Where is the liver placed? 63. What are the three uses of the 
liver ? 64. Where is the gall-bladder ? 65. How is bile made ? 
66. What does it look like ? 67. When is bile needed in the intes- 
tine? 68. How does the bile get into the intestine? 69. What 
can you say of the uses of bile? 70. What is "jaundice?" 71. 
How does the liver become diseased ? 72. What is the cause of 
gout ? 73. What effect has alcohol upon the liver ? 74. Where is 
the pancreas? 75. What is it commonly called by the butcher? 
76. What fluid is made by the pancreas ? 77. What are the uses of 
the pancreatic juice ? 78. What kinds of food are digested by the 
pancreatic juice ? 79. How does the blood take up the nourishing- 
parts of the food which have become digested ? 80. What are the 
" lacteals," what do they do, and why are they so-called? 81. Are 
the intestines usually quiet or in motion ? 82. Why is it necessary 
for them to be in motion ? 83. Mention some of the habits which 
are injurious to digestion ? 84. Explain why eating too quickly or 
too much at a time is injurious. 85. How should ice-water be 
taken ? 86. Why should we not exercise directly after meals ? 87. 
What effect has excitement of any kind upon digestion ? 88. What 
effect has alcohol and alcoholic drinks upon digestion ? 89. Where 
is the spleen ? 90. What does it look like ? 91. What do we know 
about its use ? 



104 ANATOMY, PHYSIOLOGY, AND HYGIENE. 




Fig. 49.— The Blood-vessels. 



In the right half of the figure the arteries are shown ; in 
the left half, the veins. 



CHAPTER TIL 

THE BLOOD AND THE CIRCULATION— THE HEAET AND 
THE BLOOD-VESSELS. 

217. If you cut your finger you notice a red fluid escaping 
from the wound which you call blood. If the cut be a slight 
one, only a little blood will be lost, and the accident will not 
worry you much ; but if it be deeper, you may have trouble in 
stopping the bleeding, and you would feel alarmed, for every- 
one knows how important the blood is. It is called life's fluid, 
and it deserves the name ; for if one-quarter of the blood is 
lost, life would be in danger ; and if one-third were lost, certain 
death would result. 

218. Appearance of Blood. — Blood is a thin fluid of a 
red color. If we look at the blood of an artery, the color is 
bright red ; in the veins the blood is of a dark red color. Why 
this difference exists will be explained later on. Although it 
has this red color, the fluid part of the blood is not red, but 
yellowish ; it looks red because there are a great many small 
red bodies floating in it ; these we call the blood-globules. 

219. Composition of the Blood. — The blood is composed 
of a yellowish fluid, and in this yellowish fluid we find millions 
of small bodies, mostly of a red color, which we call the blood- 
globules. 

220. Blood-globules. — If we take a drop of blood and 
look at it under the microscope, we can easily see these blood- 
globules. Even in a small drop of blood, there are about ten 
millions of them, which will give an idea of how numerous they 
are, and how many there must be in the entire body. 



106 ANATOMY, PHYSIOLOGY, AND HYGIENE. 



221. The Microscope. — This instrument has often been 
alluded to in these pages, and is constantly 
used in studying the finer structure of 
different parts of the body. Probably 
everyone knows what a magnifying-glass 
is, and has seen it used for making objects 
look larger. Perhaps, too, many of you 
have brought the rays of the sun together 
into a small spot on your hand and found 
how this burns ; on this account, the mag- 
nifying-glass is often called a burning- 
glass. Such a magnifying-glass makes 
objects appear five or six times as large as 
they really are. If several very strong 
magnify in g-glasses were placed one over 
the other in a metal tube (Fig. 50), objects 
looked at through all of them would 
appear a hundred, or even a thousand 
times larger than they really were, and 
this would constitute a microscope. 

222. Red Blood-globules. — If a drop of blood be looked 
at under the microscope, the yellow fluid is seen plainly, and 
in it we also see the blood-globules in great numbers. Most 
of these globules are of a reddish color, 
fiat, with the edge a little thicker than 
the centre ; these are called the red 
blood-globules. After the blood leaves 
the body, these red blood-globules are 
apt to stick together at their sides (Fig. 
51), and in this way columns are formed 
looking like rolls of coin piled one upon 
the other. 

223. White Blood-globules.— Be- 
sides the red blood-globules there are others which are white, 
and a little bit larger than the red (Fig. 51) ; these are not flat, 




Fig. 50.— The Microscope. 




Fig. 51. — Human Red and 
White Blood-globules. The red 
globules are seen to be flattened 
and in rolls ; the white ones are 
alone, dotted, and larger. 



THE BLOOD AND THE CIRCULATION. 



107 



but perfectly round, like a sphere, and have two or three spots 
in their centre ; there are very few of these white bodies, which 
we call white blood-globules, compared to the large number of 
the red ones. We call both the red and the white ones glob- 
ules, because of their shape, the word " globule " meaning "a 
little sphere." 

224 The Plasma. — The watery, fluid portion of the blood 
in which the red and the white blood-globules float is called the 
blood-plasma. ♦ 

225. Blood of Other Animals. — In other animals, as in 
man, the blood is red and is formed of plasma and red and 
white blood-globules. There is, 
however, one difference in some 
animals : In man the red blood- 
globules are flattened, circular, and 
perfectly clear, having no spots in 
the centre. 

In many of the larger animals, 
and in all of our domestic animals, 
the red blood-globules have this 
same shape. But in the blood of 
birds, fishes, and certain other ani- 
mals like snakes and alligators, 
which we call reptiles, the red blood-globules, while still of the 
same color as in man, are oval in shape, and have a spot in 
the centre (Fig. 52). 

226. Use of the Red Blood-globules.— The red blood- 
globules have a very important use, to explain which it will be 
necessary to say something about the air we breathe. The air 
is made up principally of two gases : One-fifth is a rich gas 
called " oxygen " — it is the gas which is necessary for life. 
The rest (four-fifths) is a gas called " nitrogen " which serves to 
dilute the oxygen so that it is not too rich and so that it is 
just right for breathing. When we breathe in air it passes 
into our lungs and stays there a short time, and while there 




Fig. 52.— The Red Blood-globules in 
Birds, Pishes, and Reptiles (on left of 
figure) as Compared with Those of Man 
(right half of figure). 



108 ANATOMY, PHYSIOLOGY, AND HYGIENE. 

the blood takes some of the oxygen from the air. In the lungs 
there are a great many small blood-vessels and the oxygen 
passes through the thin walls of these and the blood flowing 
along takes it up. The watery part of the blood cannot take 
up the oxygen, it is the red blood-globules which do this. At 
the same time the color of the blood which was dark red before 
the oxygen was taken up, changes to a bright red. After the 
red blood-globules have taken up this valuable gas, they carry it 
to different parts of the body and give it to ♦the tissues which 
have become used up, so that they become built up again. 

227. Use of the Plasma. — The fluid part of the blood also 
has a special use. When the different tissues of the body are 
being used up, they give off a poisonous gas which is called 
" carbonic acid gas" This gas is quite heavy and often collects 
at the bottom of wells or in cellars that have been dark and 
shut up for a long time. You sometimes read of people losing 
their lives by going down into such wells and cellars ; for this 
gas is so poisonous that the people cannot breathe it and they 
choke to death. If it is thought that such gas may be collected 
in old wells or cellars, men usually let a lighted candle down 
before they go ; if the candle will not burn, this is a sign that 
it would be dangerous there for a human being. For where 
this carbonic acid gas is present, the oxygen is absent or very 
little is present, and the candle requires oxygen to burn just as 
we do to breathe and live. After the plasma has taken up this 
poisonous carbonic acid gas, it carries it to the lungs and there 
it passes through the walls of the blood-vessels and escapes 
into the air. This is one of the reasons why the air which we 
breathe out is not as pure as that which we breathe in. 

228. Difference between the Blood in Arteries and 
the Blood in Veins. — The blood flowing in the arteries is of 
a bright red color, because it has just received a supply of oxy- 
gen from the air in the lungs, and has given up its poisonous 
gas to the air. The blood in the veins is of a dark red color 
because the tissues have robbed it of the oxygen which it had 



THE BLOOD AND THE CIRCULATION". 109 

before, and have given it a large supply of the poisonous car- 
bonic acid gas. The blood in veins is warmer than that of 
arteries. 

229. Clotting of the Blood.— While the blood is in the 
body and in the vessels through which it usually moves, it is 
fluid. But if taken from the body, and placed in the air, we 
find that very soon it becomes thicker and thicker, and finally 
it gets to be a soft solid, about as thick as jelly. Its shape now 
will be exactly that of the vessel in which we allowed it to get 
thick ; if we have it in a cup, for instance, it will have the shape 
of the cup. In addition to the thick part, a quantity of yellow 
fluid will also be found to have separated. Blood never be- 
comes hard, even when it solidifies ; it becomes a soft jelly-like 
solid. This change of the blood from the fluid to the solid 
state after it is removed from the blood-vessels is called clot- 
ting. The thickened blood we call a clot, while the yellow 
fluid which separates is called the serum. It is, of course, 
not natural for blood to clot ; it only happens when the blood 
is exposed to the air, or when there has been some change 
in the blood-vessel. It is rather difficult to understand why 
this thickening occurs, but if we examine the blood under the 
microscope after it has clotted we see that there are a large 
number of very fine hair-like bodies called fibres, and that these 
run in every direction and cross each other and that the blood- 
globules get caught and entangled between them ; this makes 
the blood thicken. 

230. Value of the Clotting of Blood.— This thickening 
or clotting of blood is of the greatest importance. If it were 
not for this we would have to bleed to death every time we cut 
ourselves. For when we inflict a wound, the blood flows until 
a crust forms, and this crust stops the bleeding. This crust 
is the same thickening or clotting of which we have been 
speaking and there would be no other way of stopping bleed- 
ing if it were not for this. You might press your finger on 
the wound and stop the bleeding in this way, but as soon as 



110 ANATOMY, PHYSIOLOGY, AND HYGIENE. 

you took your finger off the blood would flow again, if a clot did 
not form. 

231. The Circulation. — Thus far we have been speaking 
of the blood itself. Now we will study how the blood flows 
through the body ; for our blood is constantly moving. This 
we can see very well in the frog. If we take some part of the 
frog, as for instance, one of the thin parts of the foot, and 
spread it out and look at it under the microscope, we will see 
the blood in motion. The only reason we cannot see it in man 
is that there is no part thin enough and transparent enough for 
us to see through. If we examine the thin part of the frog's 
foot in this way we will see a number of tubes, and in the cen- 




Fig. 53.— The Blood in Motion, as Seen in the Small Blood-vessels of the Frog's Foot. 

tre a fluid full of small bodies — some red, some white — these 
are the blood-globules. It will be seen that there are a great 
many red ones and only a few white ones. And you can also 
notice that the red ones hurry along, a great many in company, 
in the centre of the stream, while there are few white ones 
which seem to rub against the wall of the blood-vessel, and 
hence, go along quite slowly. It is a beautiful sight and is an- 



THE BLOOD AND THE CIRCULATION. 



Ill 



other illustration of how wonderfully we are constructed. In 
studying the manner in which blood flows through our bodies 
it will be necessary to commence with a description of the 
heart, the arteries, the veins, and the capillaries. 



THE HEART. 



232. Situation of the Heart. — The heart is the most im- 
portant organ in the body. It is placed in the chest, having 




Fig. 54. — The Heart in Its Natural Position. It is surrounded by its sac, the pericardium : 
on each side the lungs are seen ; above, the large vessels are seen springing from it. In 
order to see all this the front of the chest is represented as having been removed. 

the lungs on each side, and covered in front by the breast-bone 
(Fig. 54) ; it projects beyond the breast-bone on each side, but 



112 



ANATOMY, PHYSIOLOGY, AND HYGIENE. 



more to the left than to the right. If the hand be placed upon 
the front of the chest on the left side the beat of the heart can 
be felt. This corresponds to the position of the pointed end 
of the heart. If the ear be placed over this Spot the sound 
made by the beating of the heart can be heard. 

233. Form of the Heart. — The heart is shaped like a cone, 
with the wide part above and the point below. It measures 
five inches from one end to the other. It is hollow (Figs. 56 
and 57), and its walls are formed of muscle-tissue. 

234. The Pericardium. — The heart is surrounded by a sac, 

called the pericardium, mean- 
ing " around the heart." Be- 
tween this sac and the heart is 
a space in which a little fluid 
is found. 

235. Cavities of the 
Heart. — The heart is hollow, 
so as to have spaces through 
which the blood can flow. It 
has four such spaces. If we 
look at the heart from the out- 
side, we can first divide it into 
two halves — a left half and a 
right half ; the right and the 
left side of the heart are sep- 
arated by a groove which runs 
from the wide part of the 
heart above to the point be- 
low. Then there is a horizon- 
tal groove, which runs across 
this vertical one and divides 
each side into two smaller 
parts, an upper and a lower. 

If we examine the interior of the heart we find four spaces ; 

the partitions which separate these spaces are placed within 




-The Heart and the Large Vessels 
Given off from It. 



THE BLOOD AND THE CIRCULATION. 



113 




Fig. 56.— Outline 
Sketch Showing the 
Arrangement of the 
Cavities of the Heart. 
A, Right Auricle ; B, 
Left Auricle ; C, Right 
Ventricle ; D, Left 
Ventricle. 



exactly where the grooves are found on the outside. So that 
each side of the heart has two spaces, an upper and a lower 
(Figs. 56 and 57). The upper spaces are 
called auricles, and the lower ventricles. Con- 
sequently, there is a right auricle and a left 
auricle, and a right ventricle and a left ven- 
tricle. The lower spaces, the ventricles, are 
much larger than the upper, the auricles. 
The wall of the heart is much thicker on the 
left side than it is on the right. 

236. Function of the Heart.— The heart 
serves to pump the blood into the blood-ves- 
sels with some force, so that it flows all over 
the body. The walls of the heart are made of 
muscle, and this muscle is constantly contract- 
ing ; each time it contracts we say it beats ; and 

when it does this the whole heart becomes smaller, and its cav- 
ities become smaller, and thus the blood is forced out. After 
this, the heart expands again, its auricles and ventricles become 
wider, and the blood flows into them from the veins until the 
heart becomes filled. Then the same thing takes place over 
and over again. 

237. Frequency of the Heart-beats. — In the grown per- 
son, the heart beats about seventy times a minute. In the 
child, it beats eighty or more. In the old person it may only 
beat sixty a minute. When sick with fever, the heart works 
more rapidly than in health, and it then often beats over a hun- 
dred a minute. 

238. Course of the Blood.— When the blood leaves the 
heart it passes from the right side of the heart to the lungs ; 
from the lungs it returns to the left side of the heart ; from 
the left side of the heart it passes into the arteries all over the 
body ; then it is returned from all parts of the body to the 
right side of the heart by the veins (Fig. 58). The way in 
which the blood circulates and its course was discovered in 



114 



ANATOMY, PHYSIOLOGY, AND HYGIENE. 



1618, by an Englishman, Harvey. It was a wonderful dis- 
covery. Before Harvey's time nothing was known about the 
way in which the blood flows. The ancients imagined the 
arteries contained air. 




Fig. 57. — The Heart (the Front has Been Removed), Showing the Interior. 



239. The Circulation through the Lungs. — All the 

blood passes from the veins into the right sicle of the heart, 
first into the upper space (auricle), and from here it flows into 
the lower space (ventricle). When these two become full of 
blood the heart contracts and squeezes out the blood into a 
large artery (the pulmonary artery), which carries it to the 
lungs. Here the blood passes into smaller and smaller arteries, 



THE BLOOD AND THE CIRCULATION. 



115 



and, finally, into the very finest tubes, which we call the capil- 
laries (from a Latin word meaning " a hair," because they are 
so very small). 

240. While the blood flows through these capillaries of the 
lung, it meets the air taken in when we breathe ; and from this 




Fig. 58.— Diagram Showing the Course of the Blood Through the Heart, Lungs, and Body 

in General. 



air it takes oxygen, and it gives to it the poisonous carbonic 
acid gas. So that in passing through the lungs the blood has 
gained oxygen and lost the poisonous gas ; and in doing this it 
changes from the dark red color it had before to a bright 
red color ; it is now purified. The capillaries soon join to form 



116 



ANATOMY, PHYSIOLOGY, AND HYGIENE. 



larger and larger tubes, and these unite to form several large 
blood-vessels, which carry the purified blood back to the heart. 
But this time it passes to the left side, of the heart, first through 
the left auricle and then through the left ventricle. When 
enough blood has flowed into the heart it contracts and 
squeezes it out into a very large blood-vessel (the aorta), which 
carries it to the tissues in different parts of the body. 

241. All this is shown very well in diagram in Fig. 58. 




Fig. 59.— The Valves of the Heart, and Between the Heart and the Large Vessels which 

Leave It. 



Starting above, we see the heart ; the shaded part to the left 
represents the right side of the heart. The impure blood 
passes from here to the lungs, gradually becoming purified 
and brighter as it passes through this organ. From the lungs 
it is seen to pass in its bright color to the left side of the heart 
(which is the portion of the heart unshaded on the diagram). 
From here we see it pass along, as the arrow indicates, to the 
different parts of the body, called on the diagram the system. 
Passing through the system and through the abdominal organs, 



THE BLOOD AND THE CIRCULATION. 117 

as shown in the diagram, the blood gradually becomes darker, 
and is shown to be carried by the large veins back again into 
the right side of the heart, the point at which we began to 
trace it. 

242. Valves of the Heart. — The valves of the heart resem- 
ble lids which are placed between the different spaces in the 
heart. They allow the blood to flow one way, but when it at- 
tempts to return in the opposite direction, they close up and 
prevent it. Fig. 59 shows them closed, thus shutting off and 
separating the different cavities of the heart. There are also 
similar valves placed between the heart and the large vessels 
which leave it. It will readily be seen how important it is that 
such a valve should exist between the left ventricle and the 
large artery which distributes the blood to the different parts 
of the body, the aorta j this valve prevents the blood from flow- 
ing back into the heart after it has been forced into the aorta. 



THE BLOOD-VESSELS. 

243. Those blood-vessels which take the purified blood from 
the heart and distribute it to all parts of the body are called 
arteries. The blood-vessels which return the used-up blood 
from the tissues to the heart are called veins. Between the 
smallest arteries and the smallest veins are the very finest 
blood-vessels, which are called capillaries. So that the blood, 
after being purified, passes through arteries, then capillaries, 
then veins. 

244. The Arteries. — The large artery which leaves the left 
side of the heart, the aorta, soon divides and subdivides, and 
these branches pass in many different directions, constantly giv- 
ing off other and smaller branches. A tree forms a very good 
example of how the arteries run in the body ; the large trunk 
of the tree corresponds to the large artery which leaves the 
heart, and the branches correspond to the branches of these 
arteries. 



118 ANATOMY, PHYSIOLOGY, AND HYGIENE. 

245. The Pulse. — When you are sick, and the doctor is 
called, one of the first things he does is to feel your pulse : he 
will put his finger upon your wrist and he will take out his 
watch. What does he do this for ? He is counting your pulse. 
If you put your finger upon your own wrist, in front, on the side 
on which the thumb is, you will feel something beating ; this is 
an artery, and the beating you feel is your pulse. Every time 
the heart beats the arteries beat, and this gives the pulse. This 
will be understood if it be remembered that every time the 
heart contracts it pumps some blood into the arteries ; every 
time another heartful of blood is forced into the arteries these 
must expand and grow wider, or else they would burst ; they 
are elastic, and hence they can expand; and it is this ex- 
pansion, or growing wider, which you feel with your finger, 
and which you call the pulse. When the doctor takes the 
pulse, he can tell how slowly or how rapidly the heart is 
beating ; for the pulse is the same in number as the heart- 
beats. The reason we usually take the pulse at the wrist 
is because it is most convenient ; but there is a pulse in 
every artery of any size in the whole body ; you can feel one 
at your temples, at the side of your neck, and in many other 
places. 

246. The Capillaries. — These are the very smallest blood- 
vessels, and they connect the arteries with the veins. We find 
the capillaries almost, everywhere. They are so small that we 
cannot see them without the use of the microscope. If you 
scratch yourself and a little blood comes, this is from some of 
the capillaries, not from an artery or vein ; for if an artery or 
vein is injured it is more serious. It is while the blood is pass- 
ing through the capillaries from the arteries to the veins, that 
the tissues take from it the oxygen and give up to it the poi- 
sonous carbonic acid gas. And after this change has taken place, 
the color of the blood has changed from the bright red of the 
purified blood in the arteries to the dark red of the impure 
blood in the veins. 



THE BLOOD AND THE CIRCULATION. 119 

247. The Veins. — After the blood has passed through the 
different tissues by means of the capillaries these unite to form 
the smallest veins, and many of these join to form larger ones, 
until finally we have a single large vein, just as we had a single 
large artery. But there is this difference : The artery started 
from the heart and went to the tissues ; the veins start at the 
tissues and gradually join into a large one which goes to the 
heart. The arteries, too, contained bright-red, pure blood ; 
the veins are filled with dark-red or purple, impure blood. 

248. Valves of the Veins. — There is still another differ- 
ence between veins and- arteries : Veins have valves (Fig. 60). 
In the arteries there is no diffi- 
culty for the blood to go any- 
where, even up-hill, because the 
heart pumps it along with quite 
some force. But there is nothing 
of this sort behind the blood in 
the veins, for by the time the 
blood has travelled through the 
capillaries it has lost the force 
given it by the heart. It would 
therefore be impossible for the 
blood to flow up-hill in the veins, 
as, for instance, in the legs, if 
there were not some arrange- 
ment for this purpose. This 

„„„„ „ ^ j. • j. • i ■ Fig. 60.— A Pair of Valves in One of the 

arrangement Consists m having Veins. They are open ; the direction of the 

valves (Fig. 60) which allow the flow of bl00d is indicated by the arrovv - 
blood to flow toward the heart, but close up, and thus prevent 
it from going in the opposite direction. 

249. Rapidity of the Circulation of the Blood.— The 
blood flows through its vessels very quickly, and it takes about 
half a minute for it to pass from the heart through the lungs, 
all through the body and back again to the heart. How many 
blood-vessels must it pass through in this short time ! 




120 



ANATOMY, PHYSIOLOGY, AND HYGIENE. 



250. Fainting. — When a person becomes pale and would 
fall if he did not hold on to something, we say he has fainted ; 
this often happens after we have been sick and we try to walk 
before we are strong enough. The proper thing to do is to lay 
the person down perfectly flat. There should be no pillow 
underneath the head. If possible, the head should even be 
lower than the rest of the body so that the blood runs into the 
head and fills the blood-vessels of the brain ; for the reason 




Fig. 61.— Method of Controlling Bleeding from a Large Wound. 



for the fainting usually is that the heart becomes weak and has 
not sufficient force to send enough blood to the brain. It is 
also important that no crowd should gather around the person, 
so that he can get all the air possible. The extremities should 
be stroked or rubbed toward the trunk, so as to facilitate the 
flow of blood . 

251. Bleeding. — If we hurt ourselves in any way and the 
bleeding is slight, it will usually stop by itself or after we ap- 
ply a little court-plaster. But suppose we have received a deep 
cut and the blood flows freely and we cannot stop it, what shall 



THE BLOOD AND THE CIRCULATION. 121 

we do until the doctor can be sent for ? We should press upon 
the injured part just above the cut. Or we can tie a string 
around it instead of pressing with the finger. For instance, if 
it is the tip of the finger which is bleeding very much, we can 
tie a string around the finger an inch or so above the cut and 
this will stop the bleeding. If it is a larger part such as the 
arm or the forearm, tie a handkerchief around the limb above 
the injury and tighten this by means of a stick which you put 
under the handkerchief and twist until it is very tight (Fig. 
61). Another name for bleeding is hemorrhage. 

252. — How to have a Good Circulation. — If we wish to 
be in good health, the circulation must be good and brisk. If 
the circulation be sluggish, we are apt to suffer in all parts of 
the body, because no part gets as much blood as it should. With 
a poor circulation the feet ai'e apt to be cold in winter, the per- 
son catches cold easily, he is quickly chilled, he may have head- 
ache, and he is not in the best of health. If we want good 
health, our circulation must be good. 

253. Exercise is the great medicine for a good circulation. 
Any good form of exercise will answer and exercise in the open 
air is the best, because while we are making our blood go 
faster we are also getting more oxygen to the tissues and build- 
ing them up quicker. Too much exercise, so as to be very 
tired, or too severe exercise, such as lifting too heavy weights, 
is injurious, because it tires out the heart and makes it weak. 
And if the exercise be much too severe there is even danger of 
bursting a small blood-vessel, though this does not happen 
often. 

254 Effects of Alcohol upon the Heart and the Cir- 
culation. — Alcoholic drink passes into the blood and irritates 
the heart, and as a result the heart may become too large. It 
might be thought that there would be no objection to having 
the heart too large ; but this is not so. For when the heart is 
not of the right size it does not act properly and sickness re- 
sults. The heart of a drunkard often contains a large amount 



122 ANATOMY, PHYSIOLOGY, AND HYGIENE. 

of fat, which weakens it and it "then has not power enough to force 
the blood into the arteries properly, and the different parts of 
the body receive too little blood and become pale and thin. 

255. You may have noticed the flushed face which some peo- 
ple have after drinking ; this is because the alcohol drives the 
blood into the blood-vessels of the skin and this becomes warm ; 
but it takes blood from other parts which are more important, 
and these suffer. 

256. The arteries of the drunkard become changed so that 
they are brittle. This often takes place in the arteries of the 
brain and they may burst ; this is what is called "apoplexy " 
and it often causes the person to fall down dead. Of course 
apoplexy may occur in persons who are not drunkards, but it 
occurs often in drunkards. 

257. Effects of Tobacco upon the Heart and the Cir- 
culation. — The use of tobacco very often affects the heart and 
causes it to throb so that the person feels it and is very much 
annoyed by it. Often it causes the heart to beat too quickly 
and then too slowly ; sometimes too strong and then too weak. 
All these effects are so common that such an irregular heart 
due to tobacco is often called by doctors tobacco heart. Of 
course, the circulation cannot be carried on properly if the heart 
acts so irregularly. 

THE LYMPHATICS. 

258. Besides the blood-vessels there are other small tubes, 
in which there flows a colorless fluid, looking like water, which 
is called lymph, and these tubes are therefore called lymphatics. 
They are shown in Fig. 62. They differ from the blood-vessels 
in not containing blood ; another difference is that all the lym- 
phatics run toward the heart. 

259. The lymphatics begin by the very smallest tubes, as 
small or smaller than the very finest capillaries. They then 
join together and form larger tubes, and finally they form two 



THE BLOOD AND THE CIRCULATION. 123 

large tubes which open into the large veins in the neck (Fig. 
62). 

260. The lymphatics help the veins in returning the used-up 
fluids of the tissues to the heart. We have already learnt that 




Fig. 62.— The Lymphatics. 

fresh, bright blood is brought to the tissues by the arteries, 
and that it circulates through the capillaries of the tissues. 
After the tissues have removed the nutritious portions, the 
used-up fluid is returned to the heart, partly by the veins and 
partly by the lymphatics. 

261. In studying digestion we found that there were certain 



124 

vessels in the abdomen which collected the nutritious juices 
from the stomach and intestines and conveyed them to the 
blood. These are called lacteals, and they are merely a part of 
the lymphatics. 

SYNOPSIS. 
The Blood : 

1. Importance — " Life's fluid," death when one-third is lost. 

2. Appearance — Thin, watery fluid ; red color, bright or dark. 

3. Composition : 

(1.) Globules : 

a. Eed — Flat, edge thicker than centre, circular in 
man and many animals ; oval and spot in centre in 
birds, reptiles, and fishes ; serve to carry the oxygen 
to the tissues; very numerous. 

b. White — Larger, dotted ; much less numerous. 
(2). Plasma — The fluid of the blood serves to carry the 

poisonous carbonic acid gas from the tissues to the lungs. 

4. Difference in Arteries and Veins : 

(1.) In arteries — Bright red ; contains more oxygen and 
less carbonic acid gas ; cooler ; purer. 

(2.) In veins — Dark red ; contains less oxygen and more 
carbonic acid gas ; warmer ; more impure. 

5. Clotting : 

(1.) Occurrence — When removed from the blood-vessels. 
(2.) Products — Clot and serum. 
(3.) Value — Serves to stop bleeding. 
The Heart : 

1. Situation — Between the lungs, behind the breast-bone. 

2. Form — Cone-shaped, pointed end downward ; hollow. 

3. Covering — Sac called the "pericardium." 

4. Structure — Muscle-tissue; a horizontal and a vertical 
groove divides it into two upper and two lower portions, a left 
and a right half. 

5. Cavities — Four: right auricle, right ventricle, left auricle, 
left ventricle. 

6. Function— To pump the blood into the lungs and all parts 
of the body through the arteries. 



THE BLOOD AND THE CIRCULATION. 125 

7. Frequency of Beats — In adults, about seventy times per 
minute ; in children, more ; in the aged, less ; in fevers, more. 

8. Valves— To separate the different cavities, when necessary, 
and to prevent the return of blood pumped into the aorta. 

The Circulation — discovered by Harvey in 1618 : 

1. From right auricle to 

2. Eight ventricle, then through pulmonary artery to 

3. Lungs ; here the blood meets the air and is purified, tak- 
ing up oxygen and losing the poisonous carbonic acid gas. 
From the lungs it returns to 

4. Left auricle, then to 

5. Left ventricle ; then it is forced into 

6. The aorta, and then through the branches of this into 

7. The arteries, carrying it to different parts of the body ; 
from these it passes into 

8. The capillaries, which join to form 

9. Veins, and these gradually grow larger, and finally empty 
into a very large one which enters the right auricle of the 
heart. 

10. Kapidity — It takes about half a minute for the blood to 
pass from the heart through the lungs and the system back to 
the heart again. 

The Arteries : 

1. Function — To carry pure, bright blood to the tissues. 

2. Origin — From the aorta, which springs from the heart. 

3. Branches — Constantly become smaller. 

4. Pulse — Owing to the contraction of the heart. 

5. Direction of Flow — From the heart to the tissues. 
The Veins : 

1. Function — To carry impure, dark blood from the tissues 
to the heart. 

2. Origin — From the capillaries, smaller ones gradually unit- 
ing to form larger ones. 

3. Branches — Gradually becoming larger. 

4. No pulse. 

- 5. Direction of Flow — from the tissues toward the heart. 
6.- Valves — To aid the flow of the blood toward the heart. 
The Capillaries : 

1. Connect arteries and veins. 



126 ANATOMY, PHYSIOLOGY, AND HYGIENE. 

2. Allow the tissues to abstract oxygen and nutritions mat- 
ters and to add carbonic acid gas and used-up fluids. 

3. Very small, can only be seen by microscope. 
Accidents to and Care of Circulation : 

1. Fainting — Due to scarcity of blood in brain ; lay person 
horizontal, with head low ; plenty of air ; rub extremities toward 
the trunk. 

2. Bleeding : 

a. If slight will stop by itself, or after use of court- 
plaster. 

b. If severe, press upon the injured part just above the 
cut, or tie something around it here. 

3. Good Circulation necessary to good health. 

4. Necessity of proper exercise to keep up a good circulation. 

5. Effects of Alcohol upon the Heart and Circulation : 

a. Enlarges heart. 

b. Weakens it. 

c. Makes heart fatty. 

d. Flushed face. 

e. Changes arteries. 

/. Apoplexy, bursting of one of arteries of brain. 

6. Effects of Tobacco upon the Heart and Circulation : 

a. Causes heart to beat too rapidly or too slowly. 

b. Causes heart to beat too weakly or too strongly. 

c. Causes heart to beat irregularly. 
The Lymphatics : 

1. Description — Small tubes containing a colorless fluid called 
" lymph." 

2. Differ from blood-vessels in not containing blood, and in 
that they all run toward the heart. 

3. Begin by very smallest tubes, which by joining together 
form larger ones. 

4. End by two large tubes, which empty into the large veins 
of the neck. 

5. Function, to help the veins in returning the used-up fluids 
of the tissues to the heart, and also to convey nutritious fluids 
from the intestines to the blood-vessels by means of the 

6. Lacteals — A part of the lymphatics. 



THE BLOOD AND THE CIKCULATION. 127 



QUESTIONS. 

1. What is meant by the words "life's blood?" 2. What happens 
if the body loses a large amount of blood? 3. What does blood look 
like ? 4. Why does blood look red ? 5. What difference is there in 
the appearance of the blood in arteries and of that in veins ? 6. Of 
what two parts is blood conrposed ? 7. Are the blood-globules very 
abundant ? 8. What is a microscope ? 9. What is it used for ? 10. 
What do you see when you look at a drop of blood under the micro- 
scope ? 11. Are any of the blood-globules white ? 12. What is the 
color of the blood of other animals than man ? 13. How do the 
red blood-globules in birds and fishes differ from those of human 
blood? 14. What is the use of the red blood-globules? 15. Of 
what gases is the air made up principally ? 16. Which is the more 
useful gas ? 17. What happens to the air when we take it into our 
lungs ? 18. What part of the blood takes oxygen from the air ? 19. 
What do the red blood-globules do with this oxygen ? 20. What do 
the tissues do with it ? 21. Of what use is the fluid part of the 
blood ? 22. What is carbonic acid gas ? 23. Is it harmless or poi- 
sonous ? 24. Where is it sometimes found outside of the body ? 25. 
How can we tell that no poisonous gas exists in cellars or at the bot- 
tom of old wells ? 26. What part of the blood takes up this poison- 
ous gas from the tissues ? 27. W T hat does the blood do with this 
poisonous gas? 28. What becomes of this poisonous gas in the 
lungs ? 29. What is the difference in color, heat, and purity of the 
blood in veins and of that in arteries ? 30. What happens if blood 
is taken from the blood-vessels and allowed to stand in the air? 31. 
What is this thickening called ? 32. What do we see when we ex- 
amine clotted blood under the microscope ? 33. Of what use is this 
clotting of the blood ? 34. What would happen when we cut -our- 
selves if the blood did not clot? 35. What is the best way of seeing 
the blood in motion ? 36. What do we see when we examine the 
circulation of the blood through the thin part of the frog's foot ? 
37. What is the most important organ in the body ? 38. What is the 
shape of the heart ? 39. What surrounds the heart ? 40. About how 
long is the heart ? 41. Of what kind of tissue are the walls of the 
heart formed ? 42. Where is the heart ? 43. Where can you feel the 
heart beat ? 44. If you put your ear over this spot what do you hear ? 



128 ANATOMY, PHYSIOLOGY, AND HYGIENE. 

45. Is the heart solid or hollow ? 46. How many spaces are there in 
the heart ? 47. How is the heart divided ? 48. How are the sides 
of the heart divided ? 49. What are the upper spaces called ? 50. 
What are the lower spaces called ? 51. Which are the larger ? 52. 
What is the use of the heart ? 53. What does the heart do when it 
beats ? 54. How often does the heart of a grown man beat in a min- 
ute ? 55. How often does the heart of a child beat per minute ? 
56. How often does the heart of an old man beat per minute ? 57. 
How does the heart beat when we have fever? 58. Describe the 
course which the blood takes. 59. Where does the blood pass to 
from the right side of the heart ? 60. Where from the lungs ? 61. 
Where from the left side of the heart ? 62. Where from the arteries? 
63. How is the blood returned to the heart from the different parts 
of the body ? 64. W T ho discovered the circulation of the blood and 
when ? 65. How does the blood get from the right side of the heart 
into the lungs ? 66. After the large artery carries it to the lung, 
where does it pass to ? 67. What is a capillary ? 68. What hap- 
pens to the blood when it is passing through the capillaries of the 
lung ? 69. How does it change its appearance while passing through 
the capillaries of the lungs ? 70. Where does the blood pass after 
it has been purified by the lungs ? 71. Where does the purified 
blood pass to after it reaches the heart ? 72. What are the valves of 
the heart ? 73. What is their use ? 74. What three kinds of blood- 
vessels are there? 75. What is an artery? 76. What is a vein? 
77. What is a capillary? 78. Do arteries branch? 79. What is 
meant by " the pulse ? " 80. How can we feel the pulse ? 81. How 
is the pulse produced ? 82. Where do we usually take the pulse, and 
why ? 83. What sets of blood-vessels are connected by the capil- 
laries ? 84. What change takes place in the blood while it is pass- 
ing through the capillaries ? 85. What differences are there between 
the vein and the artery? 86. What have the veins which the arteries 
do not have? 87. Of what use are these valves? 88. How long 
does it take the blood to travel through the entire body? 89. What 
is fainting ? 90. What should you do when a person has fainted ? 
91. Why should the head be low? 92. What should we do for 
slight bleeding ? 93. What should we do for serious bleeding which 
will not stop ? 94. What is apt to result if our circulation is slug- 
gish ? 95. What effect has exercise upon the circulation ? 96. What 
effect has too much or too violent exercise ? 97. What effect has 



THE BLOOD AND THE CIRCULATION. 129 

alcohol on the heart ? 98. What effect has alcohol on the arteries ? 
99. What is apoplexy? 100. What effect has tobacco upon the heart? 
101. What other set of tubes is there in the body besides the arte- 
ries? 102. What are the lymphatics? 103. Of what use are the 
lymphatics ? 104. What is the part of the lymphatics which we find 
in the abdomen called ? 105. Into what do the lymphatics finally 
empty ? 



CHAPTEK VHL 
THE ORGANS OF VOICE AND BREATHING. 

262. Another name for "breathing" is respiring, and hence 
the act of breathing is called respiration. When air is taken 
into the lungs we breathe in or inspire ; when the air passes 
out again, we breathe out or Exspire. 

263. Course of the Inspired Air.— When we inspire 
the air first passes through the nose, then into the throat, next 
into the sound-producing organ in the neck, the larynx ; then 
it passes through a tube running down the front of the neck, 
called the trachea or windpipe and this leads to the lungs. 

264. Each one of these parts will require special study. The 
nose will be left until the study of the sense of smell is taken 
up. The throat has already been discussed in the chapter on 
digestion (Chapter VI.). 

THE ORGAN OF VOICE-THB LARYNX. 

265. The organ which produces sound is called the larynx. 

266. Form and Situation of the Larynx. — The larynx is 
a triangular box (Figs. 63 and 69) the walls of which are formed 
of gristle or cartilage. It is placed at the upper and front part 
of the neck, and can readily be felt as a hard prominence just 
below the chin. 

267. Parts of the Larynx. — The larynx is formed of sev- 
eral pieces of cartilage joined together. The principal part is 
formed by a large triangular piece which is prominent and 
pointed in front, and can be felt beneath the skin. This 



THE ORGANS OF VOICE AND BREATHING. 131 

pointed portion is called Adam's apple ; it is larger in men 
than in women, and in some persons it stands out very much. 




Fig. 63. — The Larynx, the Trachea or Windpipe, and the Bronchi. 

Just above this triangular cartilage of the larynx, and covering 
up its upper opening somewhat, is another piece of cartilage, 



132 ANATOMY, PHYSIOLOGY, AND HYGIENE. 

called the epiglottis. Below the triangular cartilage is a circu- 
lar piece of cartilage which resembles a seal-ring in shape. 
These three pieces of cartilage, the triangular, the circular, and 
the epiglottis, form the main part of the larynx, though there 
are a few smaller pieces. 

268. Epiglottis. — This is the name given to the piece of 
cartilage, shaped like a leaf, which covers over the top of the 
larynx when we swallow. Usually it stands up straight, but in 
swallowing it is pressed down over the top of the larynx, and 
then the food slides over it into the gullet. If it be remem- 
bered that the larynx is placed in front, and that the food must 
pass across it (Fig. 67), it will be seen how important such an 
arrangement is ; but as shall soon be explained, there is an- 
other way in which the food is prevented from going into the 
larynx and windpipe. 

269. The Vocal Corcls. — If we look into the larynx, we 
will find that there is a sort of shelf projecting on each side 
(Figs. 64, 65, and 66) and that these two shelves can be moved ; 
sometimes they move toward the middle and meet each other, 
at other times they separate, and then there is a large space 
between them. These are called the vocal cords, because they 
produce the voice-sounds by their motion. 

270. Protecting the Windpipe. — The vocal cords are 
found at the upper part of the larynx ; when they come to- 
gether tightly, they close the larynx completely, so that noth- 
ing can pass into it. This is what they do whenever any food 
or solid body tries to get into the larynx or windpipe. It 
will be seen how necessary this is ; otherwise we would always 
be in danger of being choked. Sometimes the food is swal- 
lowed unexpectedly, and the vocal cords forget to close ; then 
we say the food has gone down the wrong way. This is very 
distressing, causing coughing until the piece of food is dis- 
lodged. In speaking or laughing during meals care should 
be taken that the mouth is not full, otherwise this accident 
may happen. 



THE ORGANS OF VOICE AND BREATHING. 



133 



271. The Vocal Cords in Breathing.— When we breathe 
in or inspire, the vocal cords separate widely, so as to let the 
air pass readily into the windpipe and into our lungs (Fig. 64). 
When the air passes out (expiration), the vocal cords again 




Figs. 64, 65, and 66.— Showing the Position of the Vocal Cords in Breathing and in Using 
the Voice. In Pig. 64 the cords are widely separated, as they are in inspiration : in Fig. 
65 the cords are slightly separated, as they are in expiration ; in Fig. 66 the cords are 
brought together closely, as they are when sounds are produced. 



come together, but not tightly, there being still some space left 
between the two (Fig. 65). 

272. How Sounds are Produced.— Previous to making 
a sound we always take a deep breath. Then this air is blown 
out again ; as it passes through the larynx, between the vocal 
cords, it makes these vibrate, and through the rapid motion of 



134 ANATOMY, PHYSIOLOGY, AND HYGIENE. 

the vocal cords, sound is produced. There are many differ- 
ences in the quality of the human voice, being coarse in some, 
sweet in others, high in some, low in others. Then there are 
other peculiarities of the voice, so that we can distinguish our 
friends by hearing them speak. 

273. It depends very much upon how the vocal cords are 
placed what kind of sound is produced. If the vocal cords 
are brought closely together and are made very tight the 
sound will be high. If you could look into the larynx of a lady 
with a soprano voice, while she were singing, you would find 
the vocal cords very close together ; if, on the contrary, the 
sound is produced while the cords are far apart and loose, the 
sound will be low, like that of a bass voice, for instance. 

274 Speaking. — Although sound is produced in the larynx, 
it is changed by other parts, principally the throat, the mouth, 
the tongue, and the lips. These change the sound so that 
words are spoken. With the vocal cords alone we could make 
sounds as in singing ; but to speak, we must change these 
sounds by means of the parts already mentioned. For in- 
stance, in pronouncing the word " paper," the manner in which 
the lips come together will be noticed ; if the word " law " be 
pronounced, the tongue will touch the top of the mouth. 



THE TRACHEA OR WINDPIPE. 

275. Situation and Form. — If the finger be passed along 
the front of the neck, from the larynx downward, a hard tube 
can be felt and traced down to the top of the breast-bone ; then 
it can no longer be felt, for it passes behind this bone into the 
chest. This hollow tube is called the windpipe or trachea 
(Fig. 63). It serves to conduct the air to the lungs, after it has 
passed through the nostrils, nasal passages, throat, and larynx. 

276. The Air-passage and the Food-passage. — The 
existence of another tube running along the middle of the neck 
— the oesophagus or gullet — has already been mentioned in the 



THE OKGANS OF VOICE AND BREATHING. 



135 



chapter on Digestion ; its purpose is to carry the food to 
the stomach after it has been chewed in the mouth and 
swallowed. The windpipe is 
placed in front of the gullet 
(Fig. 67); both of these tubes 
pass into the chest. The wind- 
pipe then passes to the lungs. 
The gullet passes through an 
opening in the diaphragm and 
connects with the stomach in 
the abdomen. 

277. Rings of the Wind- 
pipe. — The windpipe is 
formed of a large number of 
rings of gristle, joined together 
by a thin membrane (Fig. 63). 

278. Branching of the 
Windpipe. — After having 
passed into the chest for a 
short distance, the windpipe 

divides into two smaller tubes (Figs. 63 and 69). These 
branches are called the bronchi, there being two of them, a 
right and a left bronchus. Each carries the air from the wind- 
pipe to the corresponding lung, the right bronchial tube natur- 
ally passing to the right lung, and the left to the other side. 




Fig. (57.— The Air-passage and the Food- 
passage. The heavy line indicates the course 
of the food through mouth and gullet ; the 
dotted line shows the course of air through 
nostril into pharynx, and then into the lar- 
ynx and trachea, which are placed in front of 
the gullet. 



THE LUNGS. 

279. The lungs are the organs with which we breathe. The 
entire lung may be divided into two halves (Figs. 68 and 69), 
a right lung and a left lung. Between these two the heart is 
placed (Fig. 68). The lungs and the heart fill up the entire 
space in the chest. 

280. Shape of the Lungs. — Each lung is shaped some- 
what like a cone, with the apex above and the base below (Fig. 



136 



ANATOMY, PHYSIOLOGY, AND HYGIENE. 



69). The lungs are very light and contain a great deal of air ; 
they float when placed on water. Even after squeezing out all 
the air we can, there will still be a considerable quantity re- 
maining in the lung. 

281. Structure of the Lungs. — If we cut into the lungs, 
we find they are formed of a large number of tubes and 




Fig. 68. — The Heart and Lungs. On each side the lungs are seen ; in the centre is the 
heart ; above are the windpipe, and the lai'ge blood-vessels passing to and from the heart. 



spaces containing air. After entering the lungs each bron- 
chus divides again and again (Fig. 69), each branch, known 
as a "bronchial tube," becoming smaller, until finally the 
branches of each bronchial tube have become so small that 
they can no longer be seen without the microscope (Fig. 
70, a). 



THE ORGANS OF VOICE AND BREATHING. 137 




Fig. 69.— The Larynx, Trachea, Right and Left Bronchus, and the Lungs. The latter have 
been cut open to show the method of division and subdivision of the bronchus. 



282. The Air-Vesic I e s.— The 

smallest branch of a bronchus (Fig. 
70, a) swells so as to end in a little 
bag containing air, called an " air- 
space" (Fig. 70, b). The walls of 
these air-spaces are again subdivided 
so as to form a large number of small 
sacs called " air- vesicles." The walls 
of these air-vesicles are very thin and 
contain many blood-vessels. From 
this description it will be seen that 
the lungs really consist of a great 
collection of small sacs or spaces filled 
with air. 




Fig. 70. — The Air-vesicles, a, 
The smallest branch of the sub- 
divisions of a bronchial tube : b, 
the dilated pas-age or air-space, 
into which this expands ; c, the 
smallest spaces, air-vesicles. 



138 ANATOMY, PHYSIOLOGY, AND HYGIENE. 

283. The Pleura.— Upon their surface the lungs are cov- 
ered with a sheet of smooth membrane, called the "pleura," 
which also lines the inner surface of the chest. This smooth 
membrane allows the lungs to rub against the wall of the chest 
without pain or friction. The pleura resembles the peritoneum 
of the abdomen and serves a similar purpose. 

284. Breathing is Involuntary. — Like the beating of the 
heart, breathing takes place without the use of our will-power. 
It continues whether we are awake or asleep, and even when 
we are unconscious. It is possible to breathe faster than 
usual for a little while, or to hold the breath for a very short 
period, but these are merely temporary changes which can- 
not be continued, for breathing is not under the control of 
the will. 

285. Movements of the Chest in Breathing. — In in- 
spiration air is taken in which passes to the lungs and expands 
these. Watching the chest while this is taking place, it is 
found that the ribs rise and that the chest becomes wider. In 
expiration, the air is allowed to pass from the lungs ; these be- 
come smaller ; the ribs fall and the chest again becomes nar- 
rower. "When the lungs are filled with air, they press down 
the diaphragm ; this then crowds down upon the organs con- 
tained in the abdomen, which are pushed out ; hence the bulg- 
ing of the abdomen in inspiration. 

286. Mouth-breathing. — In breathing, the air should be 
drawn through the nose and not through the mouth. Many 
children breathe through the mouth — an injurious practice 
which results in keeping the mouth open constantly, giving 
rise to a stupid expression of the face and allowing the air to 
reach the lungs in an improperly warmed and impure condi- 
tion. 

287. Frequency of Breathing. — Usually we breathe about 
twenty times a minute. Young children breathe more often. 
After exercise, we breathe more often than twenty times per 
minute. When asleep, we breathe less frequently. 



THE ORGANS OF VOICE AND BREATHING. 139 

288. Changes which Breathing Produces in the 
Blood and Tissues. — It has already been stated that the ob- 
ject of breathing is to purify the blood. How this is done has 
also been explained. But the subject is so important a one 
that it will be well to review it briefly : The air passes into the 
air-spaces of the lungs. In the thin walls of these air-spaces 
there are a large number of very small capillaries ; in this way 
the blood in the capillaries is only separated from the air by 
very thin tissue, and gases can pass from the air to the blood 
and from the blood to the air very readily. In breathing, the 
blood takes oxygen from the air, and in exchange it gives it the 
poisonous carbonic acid gas, moisture, warmth, and a second 
poisonous gas which will be described shortly. 

289. Changes Produced in the Air by Breathing. — 
While the air passes into and out of the lungs it has oxygen 
taken from it — this is the first change. The second change is 
that it receives some of the poisonous carbonic acid gas from the 
blood. Third, it takes moisture from the blood. If you 
breathe upon the window-pane you can easily see this moist- 
ure ; and in winter when it is cold you can notice the moisture 
in the air which we expire, because it becomes visible as soon 
as it meets the cold air. Fourth, the air which we breathe out 
is warmer than that which we inspire, because it has taken 
some of the heat from the blood. 

290. Finally, the air takes from the blood a certain poisonous 
gas which has a disagreeable smell. The exact nature and the 
name of this gas is not known and it is thought to be a mixture 
of many gases. But it is known by its smell. If you come 
from the open air into a crowded room you find it disagree- 
able to breathe for a little while, because the air does not seem 
fresh ; you call it " close," and if it is very bad you say it is 
"foul." It is this bad-smelling gas which gives this odor. It 
is fortunate that this exceedingly poisonous gas has a bad 
smell, for otherwise we would not know that the air needed 
changing and was no longer fresh. If we stay in such a close 



140 ANATOMY, PHYSIOLOGY, AND HYGIENE. 

room for a little while, we no longer notice the smell, because 
we have become accustomed to it. 

291. Effects of Impure Air.^If much time be spent in 
close rooms, it produces a sleepy, dull, and tired feeling ; the 
complexion suffers and we no longer look as bright as we did. 
The blood cannot be purified in such bad air ; in this way all 
the tissues of the body become pale and weak, and the organs 
no longer work as they should. 

292. Purification of the Air.— If the air is being made 
impure constantly by our breathing, it would seem quite natu- 
ral to ask : Why is it that the air does not become so impure 
after a while that we cannot live in it ? This would result if 
God had not provided two great purifiers — sunlight and plants. 
These are the great natural purifiers and change the bad air, 
making it as good as it was before. You have no doubt no- 
ticed how stale it smells in all dark places, such as cellars,; it 
is because the sunlight never enters to purify the air. 

293. The way in which the plants purify the air is still more 
wonderful ; they make use of the poisonous gases as their 
food ; the carbonic acid gas is necessary for plants to live and 
grow. Let us stop to consider how plants live and grow. 

294 How Plants Live and Grow. — Plants breathe in 
poisonous gases from the air and breathe out pure oxygen. Be- 
sides the poisonous carbonic acid gas which they take from the 
air, they also absorb moisture and salts from the ground. 
From all these, plants form their stems and their leaves, and 
they grow, until we could hardly believe that the big tree has 
grown from a small plant with no other nourishment but what 
has just been mentioned. In order to do this, plants must 
have sunlight — they will not grow in the dark. So that what 
is poisonous to us is food to the plant. And in this way pure 
oxygen is returned to the air and the poisonous carbonic acid 
gas is gotten rid of. 

295. Ventilation. — Ventilation means allowing impure air 
to escape from our rooms and letting fresh air take its place. 



THE ORGANS OF VOICE AND BREATHING. 141 

It is very necessary. We have already spoken of the effects of 
impure air. If a man were locked in a room and everything 
were tightly closed so that no fresh air could enter, no matter 
how much food and drink he had, he would soon die, because 
his breathing would be constantly making the air of the room 
more and more impure, and finally he would die from want of 
pure air. 

296. In the summer it is quite easy to ventilate our rooms, 
for all we need to do is to open the windows wide and the 
fresh air will stream in and the impure air escape at the same 
time. But in the winter it is more difficult ; for the outside 
air, while it is fresh and pure, is also cold ; and if we opened the 
windows very wide it would cause us to feel cold. It is fortu- 
nate that our windows are not, as a rule, very tight-fitting ; 
hence more or less air gets in through the cracks. But it is 
well to draw down the window a little from the top, for the 
foul air is lighter than the fresh air and is always found near 
the ceiling of the room. 

297. Another very good way of ventilating a room is to push up 
the lower window about six inches and to fasten a piece of board 
in front of the open space which you make in this way. Or in- 
stead of a board a piece of canvas will be better yet, and it can 
be made to look nice by painting or embroidering on it. In 
this way the fresh air will come in through the canvas below, 
and the foul air will go out in the opening between the upper 
and lower portions of the window, as is shown in Fig. 71. Cer- 
tain methods of heating rooms are also valuable as means of 
ventilating them ; thus the open -grate fire is one of the best 
means of supplying warmth, because at the same time it fur- 
nishes such a ready escape for the impure air, which passes up 
the chimney. 

298. In ventilating rooms it must be remembered that there 
should be no draughts of air upon the persons in the room, for 
otherwise they will catch cold. And also that a room cannot 
be healthy if no sunlight ever enters it. In some of our houses 



142 ANATOMY, PHYSIOLOGY, AND HYGIENE. 

nowadays, and especially in what we call flats, many of the 
rooms are dark and never have any sunlight ; these must be 




Fig. 71.— A Ready Method of Ventilating Rooms. The arrows above indicate the escape 
of the impure air ; those below, the entrance of fresh air. 



unhealthy, and the air in them never can be as pure as in light 
rooms. 



THE ORGANS OF VOICE AND BREATHING. 143 

299. Effect of Tight Clothing upon Breathing.— 

Tight clothing presses upon the chest, and does not allow 
the lungs to expand as they should (Fig. 72) ; in this way not 
enough air can enter the lungs and the blood suffers, and from 
this also the rest of the body. Besides, if children dress so 
tightly about the chest it will keep the chest from getting its 




Fig. 72.— A Deformed Chest, the Result of too Tight Clothing. Compare with the natural 
chest shown in Chapter II., Fig. 18. 



proper shape and size. We should try to have as broad a 
chest as possible, and should remember always to throw our 
shoulders back, and to sit and stand erect. 

300. Effects of Tobacco-smoke upon the Lungs 
and Throat. — Tobacco-smoke is irritating to the lungs of 
many people, and makes them cough. The throat also suffers, 
and it becomes red and sore ; such a throat is called by the 
doctor "smoker's sore throat." 



144 



SYNOPSIS. 

The Organ of Voice — The Larynx : 

1. Form — Triangular box. 

2. Structure — Walls formed of cartilage. 

3. Situation — Upper and front part of neck, just below chin. 

4. Function : 

a. Passage of air to windpipe and lungs. 

b. Production of sound. 

5. Parts : 

a. Triangular piece (including " Adam's apple "). 

b. Circular piece. 

c. Epiglottis. 

d. Vocal Cords : 

(1.) Protect windpipe. 
(2.) Move in respiration. 

(3.) Produce the voice-sounds by their vibration. 
The Organs of Breathing : 

1. Larynx. 

2. Trachea or windpipe. 

3. Eight and left bronchus. 

4. Lungs. 
Trachea : 

1. Situation — Along front of neck in middle line. 

2. Form — Cylindrical tube. 

3. Structure — Eings of cartilage joined together by mem- 
brane. 

4. Function — Conveys air from larynx to lungs. 

5. Branches — Eight and left bronchus. 
The Lungs : 

1. Situation — The cavity of the chest, on each side of the 
heart. 

2. Form — Cone-shaped, with apex above. 

3. Function — To purify the blood by allowing it to be 
brought in close contact with the air. 

4. Divisions — Eight and left lung. 

5. Structure : 

a. Bronchial tubes. 



THE ORGANS OF VOICE AND BREATHING. 145 

b. Air-vesicles. 

c. Pleura, covering outside. 
Breathing : 

1. Is involuntary. 

2. Accompanied by certain movements of chest : 

a. In inspiration, chest becomes wider and ribs rise. 

b. In expiration, chest becomes narrower and ribs fall. 

3. Frequency — About twenty per minute ; more frequently 
in young children and after exercise. 

4. Changes produced in blood : 

a. Gains oxygen and becomes brighter. 

b. Loses carbonic acid gas, other poisonous gas, moist- 
ure, and heat. 

5. Changes produced in air : 

a. Loses oxygen. 

b. Has added : 

(1.) Carbonic acid gas. 

(2.) Poisonous ill-smelling gas. 

(3.) Moisture. 

(4.) Warmth. 

6. Effects of impure air : 

a. Poor health. 

b. Sleepy, dull, and tired feeling. 

7. Effects of bad habits : 

a. Mouth-breathing ; stupid expression ; air improperly 
warmed and cleansed. 

b. Tight clothing about chest .; deformed chest. 

c. Tobacco-smoke ; cough ; sore throat. 
Purification of the air : 

1. Natural : 

a. Sunlight. 

b. Plants, by using the carbonic acid gas as part of their 
food and giving back oxygen to the air. 

2. Artificial — affecting dwellings ; ventilation. 

10 



146 ANATOMY, PHYSIOLOGY, AND HYGIENE. 



QUESTIONS. 

1. What is the meaning of the word " respiration ? " 2. What is 
the definition of "to inspire?" 3. What is the definition of "to 
expire ? " 4. Through what different parts does the air pass before 
it reaches the lungs ? 5. What is the organ of voice called ? 6. 
Where is the larynx ? 7. What is its shape ? 8. How is it formed ? 
9. What is "Adam's apple?" 10. What is the epiglottis? 11. Of 
what use is the epiglottis? 12. What are the vocal cords? 13. 
How do they protect the larynx and the windpipe ? 14. How do we 
prevent food from going the wrong way ? 15. How do the vocal 
cords move in breathing ? 16. How is sound produced ? 17. What 
makes the difference in the kind of sound produced ? 18. In what 
position are the vocal cords in singing high notes ? 19. In what 
position in breathing ? 20. What other parts change the sound in 
speaking? 21. Could we speak with the larynx alone? 22. How 
can you prove that the lips and the tongue take part in speaking ? 
23. Where is the windpipe? 24. What is another name for it? 
25. Where does it lead to ? 26. What tube runs along together 
with the windpipe ? 27. Which is in front, the windpipe or the gul- 
let? 28. How is the windpipe formed? 29. Where does it end 
and what becomes of it ? 30. What are the bronchi, and where do 
they go to ? 31. What are the lungs ? 32. Where are they ? 33. 
How many are there? 34. What is the shape of each? 35. Are 
they light or heavy ? 36. Why are they so light ? 37. How are the 
lungs formed ? 38. What are the air-spaces ? 39. What are the 
lungs covered by on the outside ? 40. Do we use our will-power in 
breathing? 41. Can we stop breathing when we want to? 42. 
How do we breathe ? 43. What change do we see when we look at 
the chest while we are breathing? 44. What change if we look at 
the abdomen ? 45. Should we breathe through the mouth or 
through the nose ? 46. How often per minute do we usually 
breathe? 47. What difference is there when we exercise? 48. 
When we are asleep ? 49. What changes does breathing produce 
in the blood? 50. Where and how do these changes occur? 51. 
What changes are produced in the air by breathing ? 52. What is 
taken from the air? 53. What is given to it ? 54. What poisonous 
gases are added to the air by breathing ? 55. What makes rooms 



THE ORGANS OF VOICE AND BREATHING. 147 

smell close and foul when many people are in them and they are 
not properly aired ? 56. What are the effects of impure air ? 57. 
How is the air purified ? 58. What are the two great purifiers of 
nature ? 59. How do plants purify the air ? 60. What does the 
food of plants consist of ? 61. Can plants thrive without sunlight? 
62. What is ventilation? 63. Could we live in a room if the air 
were not changed ? 64. What is a good method of ventilating 
rooms in winter ? 65. In what part of the room do we find most 
of the impure air ? 66. Why are cold draughts undesirable ? 67. 
What effect has sunlight upon the air of a room ? 68. Can a room 
into which the sun never shines be healthy ? 69. What effect has 
tight clothing around the chest upon breathing? 70. What effect 
has tobacco-smoke upon the lungs? 71. What effect has it upon 
the throat ? 



CHAPTER IX. 
THE HEAT OF THE BODY. 

301. Have you ever stopped to think how it is that on the 
coldest day in winter our bodies remain warm, even though 
we go out into the open air ? It may be necessary to have a 
big fire in our rooms, but still our blood remains just as warm 
as in summer. You may say it is due to the clothing we wear, 
but this is not so. For if you took a cold stone and wrapped 
ever so much clothing around it, you could not warm it. Our 
clothes keep in the heat of the body, but they cannot produce 
any. 

302. The Body may be Compared to a Stove. — We 
can compare the human body to a stove, for there is some re- 
semblance in the manner in which heat is produced. The food 
which we take in by the stomach and the air which we breathe 
combine to form the "fuel," just as coal and wood form the 
fuel in the stove. This human fuel is then received by the 
organs of digestion, and changed and liquefied, so that it can 
be made use of by the various parts of the body. The blood 
distributes the fluid nourishment to the tissues of the body ; 
it also serves to relieve these tissues of the poisonous carbonic 
acid gas, and to supply them with oxygen which it has absorbed 
while passing through the lungs. As the tissues of the body 
are used up in performing the work required of them, they are 
constantly being built up again by the nourishing materials 
which the blood conveys to them. 

303. Combustion. — This process of building up the various 
parts of the body by the nutritious portions of the food, changed 



THE HEAT OF THE BODY. 149 

to a fluid form by the organs of digestion, is followed by a con- 
sumption or using up of the tissues when we use them in any 
way — in other words, when we work. This is called combustion ; 
it means a slow burning ; and is accomplished by means of the 
oxygen which the blood carries to the tissues. 

304. What Results from the Burning of Fuel— Work. 
— If we recall the resemblance of the human body to a stove, 
and the similarity of our food to the fuel, it will be instructive 
to ascertain what becomes of the fuel consumed in an ordinary 
fire. Take a locomotive, for example. Its fuel consists of coal ; 
in burning, this coal combines with the oxygen of the air — this 
is another example of combustion. As a result of this combus- 
tion, heat is produced, which changes the water in the boiler 
into steam. The steam turns the wheels of the locomotive and 
furnishes the power which draws the cars, and enables us to 
travel many hundred miles a day. 

305. Another Result of the Burning of Fuel— Ref- 
use. — As has just been explained, one result of the burning 
of fuel in the locomotive is steam, this combustion taking place 
with the aid of the air : if there is no access of air there can be 
no combustion. Besides steam there is also produced refuse — 
ashes and smoke. These are of no value, and hence they are 
correctly called /'refuse," and are allowed to escape — the smoke 
passes into the air, and the ashes are thrown away. What was 
wanted from the fuel was the steam ; this does the work, whether 
it moves a locomotive or a steamboat, or lifts an elevator, or 
pumps up water ; all these are merely examples of different kinds 
of work. Fuel, then, consumed with the aid of the oxygen of 
the air has resulted in work, which is of the greatest value to 
us, and smoke and ashes, which are refuse, and which we throw 
away. 

306. What Results from the Combustion of Our 
Food. — If, now, we examine what becomes of the food which 
is consumed by our tissues, both that which we take in by the 
stomach and the oxygen which the blood takes from the air, 



150 ANATOMY, PHYSIOLOGY, AJSTD HYGIENE. 

we find that the same things are produced, namely, heat and 
work, which are of value to us, and refuse materials, which are 
of no use to us, and which are removed from the body. It has 
already been explained how the food is changed and then is 
carried to the tissues by the blood, and also how the oxygen of 
the air is carried to the tissues. Both of these are fuel, and 
they unite with the tissues ; the oxygen unites with the tissues 
and consumes them, and then the new food builds them up 
again. It may be asked, Why must the tissues constantly be 
used up and then restored? The answer is : Because we are 
constantly doing work and require heat ; and to get these, the 
tissues must be consumed in our body, just as wood and coal 
are in the locomotive. 

307. Casting off the Refuse Materials from the 
Body. — The refuse materials, which are no longer of any use, 
which would be harmful if retained in the body, may be com- 
pared to the smoke and the ashes which escape from the loco- 
motive. These refuse materials are given off from the body in 
the form of gaseous, fluid, and solid substances. The organs 
which serve to remove them from the body are the skin, the 
lungs, the kidneys, and the intestines. The skin removes cer- 
tain poisonous gases, and also certain other materials in the 
perspiration — hence the necessity of keeping the pores open. 
The lungs, as has just been explained, remove carbonic acid gas 
and other poisonous gases in the expired air. 

308. Food and Oxygen Produce Heat and Work. — 
It does not require much study to appreciate how much work 
the body is constantly doing. Even when asleep the body is 
doing work. The heart is working faithfully, beating to sup- 
ply all parts of the body with "life's fluid" — the blood; the 
chest is rising and falling and the lungs expanding to take in 
air ; and there are many other examples of work, of constant 
work. When a man is deep in thought, it might be considered 
that he is idle and resting ; but this would be incorrect. Such 
a man is working very hard with his brain, and such work is 



THE HEAT OF THE BODY. 151 

as tiring as working with the hands. Other examples of work 
we see around us every day— the men digging, paving the 
streets, and building the houses. When hard work is required 
more food is necessary than when persons are idle. 

309. Warm-blooded and Cold-blooded Animals.— If 
you touch a stone in the street it will be cold in winter, but 
warm in summer, if the sun has been shining on it. But 
though it may feel warm, it has no heat of its own, and is 
simply warm or cold according as the air around it is warm or 
cold. If you put it in a fire it will become hot, but if taken 
out again it becomes as cold as the bodies around it. This is 
the case with all bodies which have no life. But with animals 
it is different ; they have heat of their own, and it does not 
matter whether the air around them is cold or warm, their 
blood will be about the same. Animals can be divided into 
two classes : One class, like the fishes, have cold blood ; you will 
remember how cold and clammy a fish feels. Fishes belong- 
to the cold-blooded animals. Most animals, however, have warm 
blood, and hence are called warm-blooded animals. Most of the 
animals we see are of this class. Birds have especially warm 
blood. 

310. Heat of the Human Body. — The heat of the human 
body is about 98 degrees as measured with the thermometer. 
All of you have probably seen a thermometer ; it is a long, hol- 
low tube of glass, containing a silvery fluid called quicksilver. 
Heat makes the quicksilver rise, and the more heat the higher 
it rises ; so that we tell how hot anything is by the height to 
which the fluid in the thermometer rises, there being numbers 
attached to the frame of the instrument so that we can express 
the heat ; 98 degrees expresses the heat of our blood, and 
hence this is called blood-heat. On a very warm day in sum- 
mer you may read about the thermometer having risen to 
"blood-heat ; " this means 98 degrees. 

311. The skin is never as warm as the blood. In winter the 
skin may be quite cold, especially that of the hands, and yet 



152 ANATOMY, PHYSIOLOGY, AND HYGIENE. 

the blood-heat remains the same. On the other hand, our skin 
may be very warm in summer, and still the heat of the blood 
does not rise. So that the blood and the interior of the body 
have the same heat in summer as in winter, namely, 98 de- 
grees. 

312. Heat of the Body in Sickness.— When sick with 
fever, the blood becomes hotter ; if this increase of heat is 
more than a few degrees, it is very dangerous. 

313. Regulation of the Body Heat. — In summer, when 
it is warm, there does not need to be so much heat produced in 
the body, and we naturally take less food, and wear lighter cloth- 
ing, and do not work as hard as in the cold months. In winter, 
on account of the coldness in the air, we must have an extra 
supply of body heat ; we produce this by eating more, by 
wearing heavier clothing, and by doing more work. You know 
how warm exercise makes us feel ; in winter we should take 
more exercise than at any other time of the year. Nature 
usually gives us a better appetite in winter than in summer, 
and we usually eat more meat than when the weather is warm. 

314. There is another way in which we increase the warmth 
of the body in winter ; it is by wearing warmer clothing. But 
it may be said that it has just been stated that clothes do not 
produce heat ; then why do we wear thicker and warmer clothes 
in winter than in summer ? This statement is true — clothes do 
not produce heat ; but they prevent the warmth from leaving 
the body too quickly. In winter the air is very cold, and the 
heat of the body would pass into the air very soon ; to prevent 
this we put on warm clothing. 

315. Warm Clothing. — Woollen clothing is the warmest. 
In winter it is well to wear flannel next to. the skin. In sum- 
mer, linen clothing is the coolest. Black clothes are warmer 
than white ones. This can easily be shown in the following 
way : If you take two pieces of cloth of the same kind and of 
the same size, and place them on the snow, that under the 
black cloth will be melted before that under the white one. 



THE HEAT OF THE BODY. 153 

This is the reason for wearing dark clothing in winter and 
light colors in summer. 

316. How to Keep Warm in Winter. — In winter we de- 
pend upon exercise, additional food, and warmer clothing to 
keep us warm. And all three of these must be combined if we 
want to feel comfortable. You have noticed the car-drivers 
slap their arms about on a cold day ; this is to give them exer- 
cise and make them warm ; it makes the warm blood circulate 
faster, and this brings heat to the tissues. If you stand still on 
a wintry day the feet soon become cold ; this is very un- 
healthy, and it is a sign that you should exercise in order to 
get more blood back into the feet. If we go out on a cold day 
before breakfast we feel very chilly ; everyone knows how 
much better he is able to stand the cold after having had a 
warm meal. 

317. How to Keep Cool in Summer. — In summer we 
should eat less meat and less food than in winter. Usually our 
appetite is not as good in summer as it is in winter, and natur- 
ally, therefore, we take less food. We should have light cloth- 
ing. Everything we do during the warm parts of the summer 
days we should do slowly and should not hurry. We should 
not walk in the sun for any distance without being shaded. 

318. How the Body is Kept Cool in Summer.— It 
would seem difficult to prevent the body from being over- 
heated in summer when the air around us is so warm; you 
might wonder, too, why it is that the blood of a locomotive en- 
gineer, or of a cook who is in front of a hot fire all day long, is 
no warmer than that of persons who can keep cool. . There are 
two ways in which the bodily heat is prevented from rising 
above 98 degrees when persons must be near furnaces and 
fires or are otherwise exposed to the heat. 

319. Both methods depend upon the fact that whenever 
moisture or water leaves any surface it makes that surface cold ; 
that is, it takes some of the heat of that surface with it. In 
India, the drinking-water is cooled by placing it in porous clay 



154 ANATOMY, PHYSIOLOGY, AND HYGIENE. 

vessels which allow a little of the water to soak through ; after 
it has done this, it passes off into the air and thus makes the 
rest of the water cool. If you wet your hand and then hold it 
in the air, it feels cold, because the water in passing into the 
air takes some of the heat of the hand with it. 

320. In this way our blood does not get any warmer in 
summer than in winter. For in summer more moisture leaves 
the body than in winter. Moisture leaves the body in two 
ways : By the lungs and by the skin. We breathe more rapid- 
ly in summer than in winter, especially if it is very warm, and 
in this way, more moisture is given off to the air from the 
blood passing through the lungs. Then again, the expired air 
contains more moisture in summer. 

321. Perspiration. — The moisture which passes off by the 
skin is called perspiration. This is taking place constantly 
through the pores, but in summer so much passes off that it 
collects in drops and is then called visible or sensible perspira- 
tion. 

322. Ice-water in Summer. — There is no objection to 
ice-water in summer if you do not drink too much, and if you 
take a little at a time. Some people get into the habit of 
drinking ice-water constantly ; this is very unhealthy and will 
make them suffer. But if it be remembered to drink it slowly 
and only a little at a time, it will not usually do any harm. 

323. Sunstroke. — When a person has been in the sun a 
long time, the heat of the blood may become so great that it 
makes him dangerously sick ; this is called sunstroke. It is a 
very dangerous condition. If you have to walk much in the 
sun, you should stop and go into the shade and rest as soon as 
you feel the least bit faint or dizzy. 

324. Effects of Cold.— If we are in the cold a longtime, it 
sometimes happens that we freeze the nose, ear, toes, or fingers. 
When this occurs, the frozen part of the body becomes pale or 
purple. At first it becomes painful but when really frozen it 
has no feeling at all. The reason these parts of the body 



THE HEAT OF THE BODY. 155 

freeze is because the blood does not flow in them as it should ; 
there is too little blood iu them, and so there is too little heat 
to keep off the cold. When the ears or the nose begin to 
bite we know thill they are beginning to feel the effects of the 
cold, and we should rub them so as to bring the blood back. 
When we are very cold and have frozen a part of the body, we 
should not go near the fire at once ; the change from cold to 
heat would be too sudden and the frozen parts might become 
dead. We should rub the frozen part with the hand. 



SYNOPSIS. 

Combustion — The slow consumption of the tissues : 

a. Requires food and oxygen. 

b. Produces : 

1. Life. 

2. Growth. 

3. Work and heat. 
Refuse of the Body : 

a. Gaseous, given off by : 

1. Lungs — expiration. 

2. Skin. 

b. Liquid, given off by kidneys. 

c. Solid, given off by intestines. 
Heat of Animals : 

a. Warm-blooded animals. 

b. Cold-blooded animals. 
Heat of the Human Body : 

1. About 98° in health in the interior. 

2. Colder on the surface of the skin, depending upon the 
warmth of the air. 

3. Higher in sickness (fever). 

4. Regulated by : 

(1.) Amount and kind of food. 
(2.) Amount and kind of clothing. 
(3.) Amount of exercise. 
(4.) Perspiration. 



156 ANATOMY, PHYSIOLOGY, AND HYGIENE. 

To Keep Warm in Winter : 

1. Much clothing, especially woollen ; flannel next to skin. 

2. Much food, especially meat. 

3. Much exercise. „ 
To Keep Cool in Summer : 

1. Light clothing, especially linen. 

2. Less food, and less meat. 

3. Less exercise. 

The Control of Bodily Heat in Summer — By increased escape of 
moisture by lungs and by skin. 

Undesirable Effects of Heat and Cold : 

1. Sunstroke. 

2. .Freezing parts. 

3. Bad effects of too much ice-water. . . 



QUESTIONS. 

1. What effect has our clothing upon the body heat? 2. In 
what way can the body be compared to a stove ? 3. What corre- 
sponds to the fuel of the stove ? 4. What do we call the slow burn- 
ing which takes place in the body ? 5. How does fuel do work in 
the locomotive ? 6. What results from the fuel in a locomotive be- 
sides the steam which does the work ? 7. What results from the 
combustion of our food ? 8. What does the oxygen of the air do ? 
9. Why are the tissues constantly used up and then restored ? 10. 
What gases are given off from the body ? 11. What is the object of 
taking food into our stomach, and oxygen from the air into our 
blood ? 12. What do these produce ? 13. Is the body ever idle ? 
14. What work does it do even when we are asleep? 15. Is the 
body doing any work when we think ? 16. Can a hard-working man 
get along on as little food as one who is idle ? 17. Do all animals 
have the same warmth of the blood ? 18. What is meant by a cold- 
blooded animal ? 19. Give an example. 20, What is meant by a 
warm-blooded animal ? 21. Give an example. 22. Have bodies 
without any life in them any heat of their own? 23. What is the 
heat of the human body ? 24. What is a thermometer ? 25. Is our 
skin warmer or cooler than the rest of our body ? 26. What change 
is there in the heat of the body when we have fever ? 27. What do 



THE HEAT OF THE BODY. . 157 

we do in summer so that less bodily heat shall be produced ? 28. 
Do we need more heat or less heat in winter than in summer ? 
29. How do we produce more heat in winter ? 30. Do clothes pro- 
duce heat? 31. What do they do to the heat? 32. What is the 
warmest kind of clothing ? 33. What is the coolest kind of cloth- 
ing ? 34. What color of cloth is the warmer, black or white ? 35. 
How can you show this ? 36. What should we do to keep warm in 
winter ? 37. What should we do to keep cool in summer ? 38. How 
is the body kept cool in summer? 39. Does the blood become 
warmer if we stand in front of a fire all day ? 40. What effect is 
produced when moisture passes into the air? 41. How can you 
show this effect by an example ? 42. In what ways does moisture 
leave the body ? 43. What is perspiration? 44. How does perspira- 
tion keep the heat of the body from rising ? 45. How can you take 
ice-water in summer without harming you ? 46. What is sunstroke ? 
47. What should you do to avoid being sunstruck ? 48. What are 
the effects of great cold ? 49. What parts of the body are we most 
apt to freeze ? 50. Why may certain parts of the body freeze ? 51. 
How does the nose or ear feel when it is freezing? 52. How do they 
feel when they are frozen ? 53. Should we go near the fire imme- 
diately when we have frozen a part of the body ? 54. What should 
we do? 



158 ANATOMY, PHYSIOLOGY, AND HYGIENE. 




Fig. 73.— General View of the Nervous System in the Human Being. 



CHAPTER X. 
THE NEKVOUS SYSTEM. 

325. Thus far the bony framework of the body and the 
muscles which cover and move the skeleton have been spoken 
of. The food and drink which man should take and what be- 
comes of this have been considered ; also how this food is di- 
gested and taken up by the blood, forming new tissues. The 
heart and the blood-vessels which convey the blood to all parts 
of the body have been described. The lungs and breathing 
and the effects of pure and impure air, have been studied. 
Finally, the necessity of the body having and keeping a certain 
warmth has been spoken of. 

326. These functions are found in all animals, but they are 
not peculiar to animals for they also exist in plants. The word 
" function " was defined to be the xoork which any part of the 
body does. All these different kinds of work that we have 
been studying about, and which are necessary for animal life, 
are also found in plants. 

327. Similarity in the Structure of Plants and Ani- 
mals. — The plant has a framework which corresponds to our 
skeleton, though of course it is not made of lime. This can 
often be seen in leaves that have been in the water a long 
while ; the soft parts have rotted away, leaving the stems and 
ribs of the leaf, as is shown in Fig. 74 In plants there is a 
soft green matter to clothe this skeleton. Plants take in food 
and drink by their roots and by their leaves. They also 
breathe through pores in their leaves, and take in air and give 
up air just as animals do, except that in addition they take in 



160 



ANATOMY, PHYSIOLOGY, AND HYGIENE. 



the poisonous gases and give up the pure oxygen ; this is just 
the reverse of what animals do. It may be well to explain 
what pores are : they are the very small openings in the skin 

or in the coverings of leaves ; they 
are usually too small to be seen 
by the eye without a microscope. 

328. Then again plants have sop, 
which serves as their blood ; it is 
not of a red color but it takes the 
place of blood, and, like the blood 
in animals, it carries the nutritious 
juices to the different parts of the 
plants. There are tubes which 
carry the sap, just as blood-vessels 
do the blood. Finally, plants have 
a certain warmth of their own, just 
as do animals ; it is not as great 
as in animals, but if a great many 
plants are placed in a closed room 
the air in this room soon becomes 
quite warm. 

329. Absence of Nervous 
System in Plants. — Thus it will 
be seen that plants have all the 
parts and the same functions which 

have been described in animals thus far. But now will be 
considered certain parts in animals which plants do not pos- 
sess, and the first and most important of these is the Nervous 
System. Let us first see what is meant by the word system. 
It is a collection of tissues of the same kind. So that nervous 
system is a collection of nerves, or in other words, all the 
nerves of the body taken together are called " the nervous sys- 
tem ; " all the arteries taken together would be called the " arte- 
rial system." All the muscles of the body are called the " mus- 
cular system." 




Fig. 74.— The Skeleton of a Leaf. 
After long-continued soaking in Water, 
the soft part of the leaf has been re- 
moved, leaving the woody portion 
forming the framework, which gives the 
leaf its shape and strength. 



THE NERVOUS SYSTEM. 161 

330. Most Perfect Nervous System in Man.— The 

nervous system is something peculiar to animals and does not 
exist in plants. In animals there is a great difference in regard 
to how perfect this nervous system is. The higher the form oi 
the animal, the more perfect is its nervous system. Man being 
the highest form of animal, the nervous system of man is much 
more developed than in any other animal. In some of the 
lowest animals it is very imperfect indeed. This is the main 
distinction between man and the lower animals. In other 
functions, such as respiration, circulation, and digestion, there 
are many classes of animals which are the equals of man ; but 
in the nervous system man stands far ahead of any. 

331. Function of the Nervous System. — The nervous 
system gives us information of the condition of the body and 
of what is going on around us, so that we can do what is best 
and avoid danger. It is also the work of the nervous system 
to connect the different organs of the body so that they will 
work in harmony. If it were not for the nervous system we 
would constantly be in danger of losing our lives. It enables 
us to feel, think, see, hear, etc., and in this way we avoid injury. 
When a large number of persons are working separately there 
must always be a head or chief to direct them. Imagine what 
disorder there would be in the class-room if every pupil did as 
he or she wished and there were no teacher. Think of an army 
of soldiers over which there were no general, and every soldier 
did as he wished ; how dreadful the confusion would be ! In the 
same way there would be great disorder among the organs of 
our bodies if there was not something to connect them and to 
direct their work ; this is done by the nervous system. 

332. Divisions of the Nervous System. — We can divide 
the nervous system into certain parts. These parts are all con- 
nected. We separate them only for the purpose of study. 

333. There is first the brain, the head or chief that superin- 
tends the entire work of the system, just as the president of a 
railroad manages the running of all the trains. The brain is 

11 



162 ANATOMY, PHYSIOLOGY, AND HYGIENE. 

placed in a rounded, bony box, made by the bones of the skull, 
called the cranium. 

334. Next we have the spinal cord, which is still very im- 
portant, though not so important as the brain. It is a sort of 
assistant to the brain, relieving it of a good deal of work, and 
also doing some work which the brain does not do. The spinal 
cord runs in the canal or tunnel which we find in the back part 
of the vertebree. 

335. Finally, we have the nerves. These are sent out from 
the brain and from the spinal cord to different parts of the 
body ; they also run in the opposite direction — from the various 
parts of the body to the brain and spinal cord. They are the 
messengers, or the telegraph wires so to speak, which carry the 
wishes of the brain to the different parts of the body ; and they 
also carry messages from the different parts of the body to the 
brain. These different parts of the nervous system are illus- 
trated in Figs. 73 and 79. 

336. Examples of the Action of the Nervous System. 
— The uses of the nervous system can best be understood by a 
few examples. Suppose a man is walking along the street and 
is about to cross the car-track. His ear hears the jingle of the 
bells and by means of a nerve sends a message to the brain ; 
the brain then sends an order along the nerves of the eyes to 
these organs to look in the direction in which the ear has heard 
the sound and to see whether a car is approaching. The eyes 
obey the orders of the brain and look and see the car very near, 
and also perceive that the person is in danger of being run 
over. They immediately send back word to the brain about 
this danger. Then the brain sends word to the muscles which 
move his legs ; this message is also transmitted by nerves ; it 
tells these muscles to act immediately. The result is that they 
obey ; he quickens his steps and thus escapes the coming- 
car. 

337. Let us take another example. Suppose it is time for 
the noon recess ; you have taken your breakfast early in the 



THE NERVOUS SYSTEM. 163 

morning and have had no food since. The stomach sends a 
message to the brain that it has been empty for some time ; the 
tissues also send messages by numerous nerves that they would 
like some more nourishment since they have exhausted all that 
the blood had to give them. Upon receiving these messages, 
which, in short, mean that you are hungry, the brain gives out 
its orders. It directs the legs to carry you home as soon 
as school is dismissed ; it directs them to take you to the 
dining-room and to seat you at the table ; it directs the 
eyes to look at the food and see whether it is wholesome ; 
it orders the hands to seize knife and fork and to convey 
food to the mouth ; the jaws are directed to chew it, the 
throat to swallow it and the stomach to digest it. All this the 
brain does. 

338. Rapidity of Action of the Nervous System. — It 
has taken a little while to describe these two examples of the 
manner in which the nervous system acts, but it must not be 
imagined from this that so much time is consumed. All these 
messages are sent back and forth with lightning-like rapidity, 
and it only takes a very small part of a second for a message to 
travel from the tip of the finger to the brain and back again. 



THE BRAIN. 

339. Coverings. — The brain is a large, rounded mass of 
soft nervous tissue which is contained in the oval box of bones 
formed by the skull. These flat bones which cover it protect it 
from injury. Besides these, it is covered on the inside of the 
skull by three membranes or sheets of tissue ; it is therefore 
very well protected. 

340. Size and Weight of the Brain.— The brain is about 
eight inches long. If looked at from above (Fig. 75) it appears 
hemispherical ; if viewed on its under surface (Fig. 76) it is fiat. 
It weighs about forty -seven ounces on the average — about three 
pounds. The brain of a man is larger and weighs more than 



164 ANATOMY, PHYSIOLOGY, AND HYGIENE. 

that of a woman. It was formerly thought that highly educated 
persons had very heavy brains, but this is not so in every case. 
It is true in certain cases, however, for the brain of Daniel 
Webster weighed sixty- three ounces. On the other. hand, the 
brain of Gambetta, who was one of the brightest statesmen 




Fig. 75.— The Brain, Upper Surface. 

France ever had, was said to weigh only thirty- five ounces. So 
that there are exceptions to this opinion. However, the brains 
of idiots are always small and light in weight. It will be ex- 
plained further on in what way the brain of a very intelligent 
man differs from that of an idiot. The human brain is heavier 
than that of any other animal except the whale and the ele- 
phant. 



THE NERVOUS SYSTEM. 165 

341. Divisions of the Brain. — The brain is divided into 
three parts : There is first the greatest part of the brain, the 
large, round mass which you see when you look at it from 
above, and which forms about seven-eighths of the entire brain ; 
this is called the cerebrum (Figs. 75, 76, 77, and 79). 




Fig. 76. -The Brain, Lower Surface. 

342. Then beneath the cerebrum, at the back part, is a 
smaller portion, looking like two pouches ; this forms only one- 
eighth of the entire brain, and is called the cerebellum, or the 
little brain (Figs. 76, 77, and 79). 

343. Third, there is the portion which is a sort of bridge be- 
tween the brain and the spinal cord ; this is called the medulla 
(Figs. 77 and 79). 



166 



ANATOMY, PHYSIOLOGY, AND HYGIENE. 



344. The Cerebrum. — As already stated, this is the main 
part of the brain. If you look at it from above you will see that 
it dips in along the centre, and you will find this cleft to be quite 
deep, separating the brain into two halves ; these are called 
the hemispheres — a very appropriate name. The surface of the 
cerebrum is very uneven, due to the fact that it is covered by 
a great many winding elevations, between which the surface 




Fig. 77.— The Brain, Looked at from the Side, Showing Very Nicely the Divisions of the 
Brain. The large mass above is the cerebrum ; the smaller portion, below and behind, is 
the cerebellum. From the cerebrum above, a cylindrical portion is seen passing directly 
downward to the end of the illustration below, this is the medulla ; the cerebellum is seen 
to be connected with its upper and back part. 



dips in about an inch. In a person whose brain is very much 
developed and who is very bright, these elevations are very 
winding and complex, and between them the brain matter dips 
in very much ; while in the lower animals the elevations are 
quite straight and simple, and there is very little dipping in 
between them. 

345. Gray and White Parts of the Cerebrum.— On the 
outside the cerebrum is gray, but internally it is white. The 



THE NERVOUS SYSTEM. 



167 



gray part consists of cells — that is, small bodies with a number 
of branches given off from them, and these branches connect 
with the nerve-fibres. The interior of the cerebrum is white, 
and is formed by millions of 
nerve-fibres (Fig. 78). 

346. The Cerebellum.— 
This, like the cerebrum, is gray 
on the outside and white within. 
It is much smaller than the ce- 
rebrum, and is placed behind 
and below it, being covered in 
by it (Figs. 77 and 79). 

347. The Medulla (Figs. 77 
and 79) serves to connect the 
brain with the spinal cord. It 
is very important. There is one 
part of it which, if it becomes 
injured in any way, will produce 
instant death. 

348. The Cranial Nerves. 
— What is a nerve ? A nerve 
is a collection of nerve-fibres 
forming a small cord. These 

nerve-fibres are very small, and can only be seen with the mi- 
croscope. But when a great many of them run alongside of 
each other they are joined into a bundle, and this we call a 
nerve. Some nerves are very large and others quite small. At 
the ends, where they pass to the tissues, they are very small 
indeed. 

349. The brain gives off twelve sets of nerves, and these all 
pass to the tissues of the head and face. They are important, 
for among them are the nerves of smell, taste, sight, and hear- 
ing. There are small holes in the bones of the skull by which 
these nerves pass out. It has already been stated that the 
cranium is the bony box in which the brain is contained ; 




Fig. 78. — A Portion of the Cerebrum 
Cut Across, Showing the Gray Border on 
the Outside and the White Matter Within. 



168 ANATOMY, PHYSIOLOGY, AND HYGIENE. 

lience these nerves are called cranial, because they come from 
this bony box. They are arranged in pairs, one behind the 
other ; on this account they are often called in numerical order, 
first, second, third, etc. 

350. Functions of the Brain. — The brain is the seat of the 
mind, of the will, of thought, of memory, and of intelligence. 
It is through the brain that we are rendered superior to the 
lower animals. The lower animals accomplish different actions 
through what we call "instinct," that is, without the action of 
the mind. But we can do many more things than they, and 
more difficult acts, because our brains are more developed. 

351. Let us examine into the work of the brain and see what it 
does for us : In the first place, it is where the will exists ; it is 
where our desires come from. Then as to memory, it is the 
brain which enables us to think about things and to remember 
names, figures, faces, and all other things. Imagine how useful 
this is and how difficult it would be to get along without it ! 
Think also of the wonderful action of the brain when it is pos- 
sible to remember things all our lives ! 

352. The brain gives us reason, so that when we see a thing 
we know what it means and whether it is important or not. It 
gives us judgment which enables us to do the right thing iu 
order to accomplish what we want. 

353. Intelligence has its seat in the brain. This prevents 
us from being stupid ; it enables us to understand thiugs and 
allows us to express ourselves just as Ave wish, by language. It 
enables us to see the difference between right and wrong, so 
as to avoid the latter. 

354. Training of the Brain. — A great deal of our mem- 
ory and intelligence depends upon the way in which our brain 
is trained. If we use our brain a great deal, it will become 
better than if we allow it to remain idle. Many things which 
we study at school are taught us for the purpose of training 
the brain. We should remember that we cannot think of more 
than one thing at a time. When you study your lessons, you 



THE NERVOUS SYSTEM. 169 




Fia. 79.— The Brain and Spinal Cord, with the Spinal Nerves Issuing from the Latter. 



170 



ANATOMY, PHYSIOLOGY, AND HYGIENE. 



should not think of play ; and when you play, you should en- 
joy yourself, and need not think of your studies. There is a 
time for play and a time for study. 



THE SPINAL CORD. 



355. The spinal cord is the soft bar of nerve-tissue which 
runs down from the brain through the canal of the backbone. 
It is about as thick as the thumb. Besides being protected by 
bone, it has, like the brain, a covering of three membranes. 
"While the spinal cord is not as important a part of the nervous 
system as the brain is, it is still very important, especially the 
part which runs through the neck. One often hears of peo- 
ple falling down stairs and " breaking their necks ; " what is 
meant by this is that this upper part of the spinal cord is 
broken and death occurs immediately. When murderers are 
hanged they die, because in hanging this upper part of the 
spinal cord is broken across. 

356. If the spinal cord be sliced across it would be seen 
that although it is white on the outside, it is gray on the in- 
side. This gray matter in the 
interior is arranged in a pe- 
culiar manner, resembling two 
crescents joined together, as is 
shown in Fig. 80. As in the 
brain, this gray part is formed 

y±~ of cells, while the white portion 

consists of nerve-fibres. 

Fig. 80.— A Portion of the Spinal Cord 357. Spinal NerVeS. The 

Cut Across, Showing the Gray Crescents in \ 

the Interior Surrounded by the White nerves which leave the brain are 

Nerve Material. . . 

called cranial nerves ; those which 
leave the spinal cord are called, in the same way, spinal nerves. 
There are thirty-one pairs of spinal nerves ; they are connected 
to the side of the spinal cord in a line. Each nerve when it 
leaves the spinal cord consists of two parts, one in front and 




THE NERVOUS SYSTEM. 



171 



nerves 



the other behind ; but these two portions soon unite to form a 
single nerve. 

358. Kinds of Nerves. — There are two kinds of nerves — 
the nerves of sensation and the nerves of motion. The 
of sensation are those which give feeling to different 
parts of the body and especially to the skin ; when 
you cut or burn yourself it is a nerve of sensation 
which carries the message of pain to the brain. 
The nerves of motion are those nerves which go to 
the different muscles and cause them to act when 
the brain wishes it. 

359. Functions of the Spinal Cord.— The 
spinal cord is a sort of agent or assistant to the brain, 
and it also serves to carry the large number of 
nerve-fibres which leave the brain, travel through 
the spinal cord and then to the limbs. But besides 
this, the spinal cord has a very important use : 
When the brain is engaged at something else, the 
spinal cord takes its place, and acts for it if any oc- 
casion arises. 

360. Reflex Action. — This action without the 
knowledge of the brain is called reflex action, and 
it is the spinal cord which carries it out. Let us 
take a few examples of reflex action : Suppose you 
want to go to school in the morning. Your brain 
directs the muscles of your lower limbs to move in 

such a manner that you walk. But after you have started 
walking, you do not need to think about it ; perhaps you reach 
school and have crossed many streets and have turned many 
corners without knowing it. It was the spinal cord which 
looked out for all this. 

361. If a fly alights upon your face, you put up your hand 
to brush it off, without really thinking of it. This is another 
example. 

362. During sleep reflex action is shown very well. If you 



Fig. SI.— A 
Nerve, Very 
Highly Mag- 
nified, Show- 
ing How it is 
Made up of 
Numerous 
Nerve-fibres. 



172 

tickle the feet of anyone who is asleep, he will draw up his 
lower limbs so as to draw them away ; all this will be done 
without waking. It is the spinal cord which looks after this. 
In the same way, if you walk along, thinking of something else, 
and suddenly some one appears before you and makes a motion 
as though to strike you, you will draw up your arm to protect 
yourself before you can realize that anyone is there. If some 
one makes believe striking you in the face, you cannot help 
closing your eyes — you cannot keep them open even if you want 
to. This is reflex action. It is also reflex action which ex- 
plains how it is that a chicken can run around after its head is 
chopped off. 

363. Sleep. — Sleep is the natural rest of the brain. Just as 
every other part of the body needs rest during each twenty-four 
hours, so does the brain. In fact, many other parts of the body 
can exist longer without rest than can the brain. We may 
rest any other part of the body without sleep ; but the only 
sign that the brain is resting completely, and is not active, is 
sleep. 

364. The Amount of Sleep which is necessary varies 
with different people. Men who think a great deal require 
more than those who do bodily work. The average sleep neces- 
sary for a man is from seven to eight hours. 

365. Children require more Sleep and should have 
nine or ten hours, for while the body is growing rapidly more 
rest is needed. 

366. Uses of Sleep. — During sleep the brain and all 
other parts of the body rest and regain the strength which they 
have lost by the day's work. 

367. Time for Sleep. — Night is the time for sleep. Per- 
sons who work at night and sleep by day are not usually quite 
as bright and healthy as those who sleep during the natural 
time. Young people who dance all night and then sleep by 
day to make up for it, soon look pale and tired out, and often 
weaken their bodies so much that they become sick. The 



THE NEKVOUS SYSTEM. 173 

proper time for children to go to bed is at nine or ten o'clock ; 
they should then rise at six or seven. 

368. Nervousness. — We often hear people say they are 
" nervous." By this they mean that their nervous system is out 
of order. They start at the least noise ; they become cross and 
irritable ; and the rest of the body suffers. Nervousness is 
often due to too little sleep or too much excitement. Very 
often, too, it is due to indigestion, or to coffee, tea, or tobacco. 
When we are nervous we are apt to do things in haste, and are 
apt to talk cross and to get angry easily. All these things we 
should be careful to avoid. 

369. Wakefulness. — When unable to sleep at night, we are 
said to suffer from sleeplessness or ivalcef illness. Lying awake 
at night when all is quiet and everyone else is asleep is very 
annoying. Not only does the body remain tired after the day's 
work, but the person becomes worried and cross because he 
cannot sleep. There are, of course, many causes of being una- 
ble to sleep, but some of the most common are laziness, coffee, 
tea, and tobacco. It is quite natural for us to feel a little tired 
at night, and then we will have no trouble in falling asleep ; 
but if we are idle all day long, we do not feel tired, and on this 
account we may find it hard to fall asleep. Coffee, tea, and 
tobacco excite the nervous system, and on this account prevent 
sleep. 

NARCOTICS. 

370. Narcotics are drugs which benumb the brain and thus 
produce an artificial sleep. The sleep produced by narcotics is 
not refreshing like natural sleep, but persons often wake up 
stupid and with a headache. The narcotics used most fre- 
quently for producing sleep are chloral and opium. 

371. Chloral comes in white crystals which dissolve in 
water. People sometimes get in the habit of taking it 
regularly to make them sleep, and soon they cannot do with- 



174 ANATOMY, PHYSIOLOGY, AND HYGIENE. 

out it ; and they have then what is called the chloral habit. 
They become nervous, pale, and weak, and have indigest- 
ion. 

372. Opium . — This is a narcotic, but it is probably the most 
useful medicine there is when ordered by the doctor in the 
proper cases which need it. It is a brown, sticky substance, 
or it may come in the form of a brown powder. Most of it 
comes from India and the warm countries of this neighbor- 
hood. It is the juice of the unripe fruit of the poppy-plant ; 
this juice is allowed to dry and then makes this sticky sub- 
stance. With water we can extract white crystals, which have 
the same effect on the body as opium itself ; these crystals are 
called morphine. 

373. Everyone has probably heard of the opium habit, or, 
what is the same thing, the morphine habit. It is a habit peo- 
ple get into of taking these drugs whether they need them or 
not. It has already been said, that morphine and opium are 
very useful medicines when the doctor orders them and they 
are needed. They take away pain, and they make persons 
sleep when they are sick and restless ; in such cases they do a 
great deal of good. 

374 The Opium, or Morphine Habit. — But persons 
who have the " morphine," or " opium habit," do not take the 
drug for this purpose ; they take it because they think it makes 
them feel good for the time being, and makes them forget any 
cares they may have. But after the effects pass off, they feel 
miserable. The stomach is upset, they are tired and nervous, 
have a very bad headache, and often feel like vomiting. They 
feel so bad that they take more and more, until finally they 
keep under the effects of it all the time. Some of them take 
the narcotic by the mouth, others smoke it in long pipes. There 
is still another way in which these wretched people take mor- 
phine, and that is by piercing the skin with a hollow needle. 
Some of the morphine, dissolved in water, is forced under the 
skin from a small glass tube which is attached to the hollow 



THE NERVOUS SYSTEM. 175 

needle. This is probably the most dangerous way of taking 
the drug, when used merely as a habit. 

375. Many persons who have this horrible habit have com- 
menced very innocently. Their doctor may have ordered the 
drug for them at a time when they needed it. But instead of 
stopping its use when they were well, perhaps they have con- 
tinued it, imagining it made them feel better, until it was too 
late, and they were prisoners of the habit. It is a habit which 
is more difficult to break off than any other habit ; it is worse 
to stop than either drinking or smoking. 

376. The effects of the opium and morphine habit upon the 
health show themselves very soon. The poor wretch soon be- 
comes nervous ; he cannot sleep at night ; he has no appetite ; 
if he takes any food he cannot digest and often vomits it ; he 
becomes thin and has a yellow complexion ; his mind changes 
and he loses his memory ; he has no longer the power to do 
right, and he is known to tell lies without hesitation in order to 
get some of the drug. He becomes worse and worse, until, 
finally, when he has no more money to buy the drug, and his 
health is all broken up, he dies in the hospital or lunatic asy- 
lum, or often commits suicide. This is a horrible picture that 
has been drawn, but a true one. 

377. Cocaine. — Lately, a very important medicine has been 
used to take away pain when painted on a part which is pain- 
ful ; it is called cocaine. This is also taken internally, and some 
persons have gotten into the habit of taking it regularly. It 
excites them and makes them feel rested and it removes tired 
feelings for a time. But this is only temporary and soon the 
person feels worse than before. If he gets into the habit of 
taking the drug regularly, it makes him nervous, and he gets a 
great many of the symptoms which were spoken of as occurring 
in the opium habit ; this habit often affects the mind, and the un- 
fortunate person becomes crazy as a result of the cocaine habit. 

378. Effects of Alcohol upon the Nervous System. — 
The nervous system has no greater enemy than alcohol. Every 



176 ANATOMY, PHYSIOLOGY. AND HYGIENE. 

part of the nervous system — the brain, the spinal cord, and the 
nerves — suffers when large quantities of alcoholic drinks are 
taken. The brain becomes affected very soon. If a large quan- 
tity is taken at one time and the person becomes intoxicated, 
he becomes stupid in his intelligence, but excited in other 
ways — he sings, or cries, or begins to laugh like a fool or be- 
gins to scold, and he often fights. He forgets that he is a 
human being and acts like a brute. He is unable to walk 
straight and staggers along in a pitiable way, catching on to 
lamp-posts or any other place for support. The stomach be- 
comes affected and he vomits. The effect upon the nerves is 
shown by the way every part of his body trembles, and the 
great unsteadiness. A drunken man is a disgusting sight ! 
And if this be repeated many times and becomes a habit, 
the memory begins to fail, the person becomes bloated and fat 
but very weak, his health fails, his hands tremble, his eyes and 
nose are constantly bloodshot, he becomes dirty and careless, 
and the individual changes into a good-for-nothing. 

379. Delirium Tremens. — As a result of drunkenness 
there is often produced a disease of the nerves called delirium 
tremens. This means that the person is out of his mind and 
has trembling of the body. It is a condition which kills many 
men, and which is dangerous to the drunkard, because he gets 
out of his mind and tries to do all sorts of violent things, espe- 
cially to jump out of the window. He imagines that he sees 
animals such as mice, rats, and snakes, and he thinks these are 
chasing him, and he wants to run away. It is difficult to keep 
him quiet. The whole body trembles from the poisonous ef- 
fects of the alcohol. The heart is often weakened so much 
that the person dies because this organ has become too weak. 

380. Effects of Tobacco upon the Nervous System.— 
This shows itself chiefly by the trembling hands and the ner- 
vousness which we often notice in people who smoke a great 
deal. Many persons, especially young men, cannot smoke at all 
without producing nervousness. 



THE NERVOUS SYSTEM. 177 

381. Effects of Coffee and Tea upon the Nervous 
System. — Coffee and tea excite the nervous system. They 
are often the cause of nervousness and trembling* ; also of pal- 
pitation of the heart, which is a form of nervousness. Children 
should not drink coffee or tea, as they do not need any stimu- 
lants — certainly not until they are full-grown. 

382. The Sympathetic System of Nerves.— Besides the 
great nervous system to which this chapter has been devoted, 
there is a smaller collection of nerves, which is known as the 
sympathetic system. Along the front of the backbone are found 
two nerves, with many knob-like enlargements at numerous 
points. This is the central part of the sympathetic system ; 
from it the branches of this system are given off. Unlike the 
nerves of the general nervous system, which pass to the outside 
of the body and to parts which are subject to our will, the 
branches of the sympathetic system pass to the internal organs 
which cannot be controlled by our will, and which are there- 
fore called " involuntary." 



SYNOPSIS. 

The Nervous System : 

1. Present in animals, but not in plants. 

2. Functions : 

a. To give information in regard to the condition of va- 
rious parts of the body. 

b. To give information of what is going on around us, so 
that we can act accordingly, and can avoid danger. 

c. To connect the different organs of the body, so that 
they can act in harmony. 

3. Divisions : 

a. The general nervous system ; nerves passing to ex- 
ternal parts, and those controlled by our will. 

b. The sympathetic nervous system ; main part arranged 
in two chains, with knob-like enlargements along the front 
of the vertebral column ; from these branches are given 

12 



178 ANATOMY, PHYSIOLOGY, AND HYGIENE. 

off ; branches pass to internal organs which are not under 
control of the will — " involuntary." 
The General Nervous System : 
Divisions : 
A. Brain : 

1. Coverings : 

a. Membranes. 

b. Bones forming cranium. 

2. Shape — hemispherical. 

3. Size — about eight inches long. 

4. Weight — a. Average about forty-seven ounces. 

b. Heavier in man than in woman. 

c. Very light in idiots. 

d. Weighs more in man than in any other ani- 
mal, except the whale and elephant. 

e. In some cases, weight is proportionate to in- 
telligence. 

5. Gives off the cranial nerves. 

6. Natural rest — Sleep : 

a. Necessary amount varies. 

b. Hard work necessitates more. 

c. Average for man, seven to eight hours. 

d. Children require more, nine to ten hours. 

e. Use, to give body, and especially brain, a 
complete rest. 

/. Proper time, at night. 

g. Disordered sleep — wakefulness — may be due 
to laziness, tea, coffee, or tobacco. 

7. Divisions : 

a. Cerebrum : 

1. Largest part of brain (seven-eighths). 

2. Large, round mass. 

3. Divided into halves, called hemispheres. 

4. Surface uneven, owing to winding eleva- 
tions, between which the surface dips in. 

5. The height of these elevations and de- 
pressions is proportionate to the intelligence. 

6. Exterior gray and formed largely of 
cells. 



THE NERVOUS SYSTEM. 179 

7. Interior white, and formed entirely of 
nerve-fibres. 

8. Controls mind, will, thought, memory, 
and intelligence. 

9. Gives reason and judgment, elevating 
man above the lower animals. 

10. Admits of training. 

b. Cerebellum, or " little brain." 

1. Much smaller than cerebrum. 

2. Forms one-eighth entire brain. 

3. Forms lower and hind part of brain. 

4. Like cerebrum, is gray on outside and 
white within. 

c. Medulla : 

1. Connection between brain and spinal 
cord. 

2. Very important part, since injury to one 
portion causes instant death. 

B. Spinal Cord : 

1. Long bar of nerve- tissue. 

2. Protected by : a, membranes. 

&, bones forming vertebral column. 

3. Interior formed of gray matter, arranged in cres- 
cents, and composed largely of cells. 

4. Outside is white and formed of nerve-fibres. 

5. Gives off the spinal nerves. 

6. Acts as an agent or assistant to the brain. 

7. Controls reflex action — action without the knowl- 
edge of the brain, serving to protect us from injury. 

G. Nerves : 
Divisions : 

1. According to action : a, sensation; b, motion. 

(1.) Nerves of sensation, carrying impres- 
sions of feeling, such as pain, etc., from the 
surface to the brain and spinal cord. 

(2.) Nerves of motion, carrying messages 
from the brain and spinal cord to the muscles, 
and causing these to act. 

2. According to source : a, cranial ; b, spinal. 



180 ANATOMY, PHYSIOLOGY, AND HYGIENE. 

(1.) Cranial nerves, twelve pairs, pass from 
brain, through openings in bone, to various 
parts of the head and neck. 

(2.) Spinal nerves, thirty-one pairs, emerge 
from spinal cord by two roots, which soon 
join together, pass to different parts of the 
trunk and limbs. 
Disorders of the Nervous System, due to : 

1. Coffee and Tea: 

a. Often excite nervousness, trembling, etc. 

b. Children should not be allowed any. 

2. Tobacco — Often causes nervousness, trembling, etc. 

3. Alcoholic Excess : 

a. Great enemy to nervous system. 

b. Stupefies intelligence. 

c. Excites brain in undesirable ways, such as fighting, 
etc. 

d. Causes trembling and staggering. 

e. Other effects on rest of system. 

/. Delirium tremens — Result of drunkenness, person out 
of mind ; great trembling ; person violent, often wishing to 
jump from window ; person imagines he sees enemies, mice, 
rats, snakes, etc. ; heart often seriously weakened, and may 
die from this cause. 

4. Narcotics — Produce an artificial sleep, which lacks the re- 
freshing qualities of natural sleep. 

a. Chloral : 

1. Often taken to produce sleep. 

2. Danger of habit, so that a person cannot sleep 
without it. 

3. Chloral habit causes nervousness and other bad 
effects upon system. 

b. Opium : 

1. Useful as medicine when prescribed by the phy- 
sician. 

2. Contains white crystals called " morphine," which 
have the same effect as does opium. 

3. Persons often acquire the habit of taking it by 
mouth, smoking, or beneath the skin. 



THE NERVOUS SYSTEM. 181 

4. The opium habit is very injurious, and is the 
most difficult to break. 

5. As a result of the opium habit, the health suffers 
very much ; the poor victims often end their lives in 
hospitals and lunatic asylums, or attempt suicide. 

5. Cocaine — A new drug, used to relieve pain, when painted 
on certain surfaces ; it is not a narcotic, but it presents the 
same danger as in opium, of having the person become in the 
habit of taking it regularly. The cocaine habit causes weak- 
ness of the nervous system, and often ends in insanity. 
The Sympathetic Nervous System— (see above). 



QUESTIONS. 

1. What different parts are found in plants as well as in animals ? 
2. What is the skeleton of a leaf ? 3. Do plants take in food and 
drink? 4. How? 5. How do plants breathe? 6. What differ- 
ence is there in the breathing of plants and of animals ? 7. What 
are pores ? 8. What fluid is there in plants corresponding to the 
blood of animals ? 9. How is the sap carried along ? 10. Do plants 
have any warmth of their own? 11. How can you prove this ? 12. 
What part of animals is absent in plants ? 13. What is a system ? 
14. Give an example. 15. Does the nervous system exist in plants ? 

16. In what animal is there the highest form of nervous system ? 

17. What is the function of the nervous system ? 18. What might 
happen if we did not have a nervous system ? 19. Give an example 
to show that there must be a chief to everything where there are 
many parts. 20. Into what parts can we divide the nervous system ? 
21. What is the office of the brain ? 22. What of the spinal cord? 
23. What of the nerves ? 24. Give an example of the action of the 
nervous system. 25. Does it take the nervous system a long time 
to act ? 26. Give an example to show how quickly it acts. 27. 
Where is the brain situated ? 28. What protects it ? 29. Is it soft 
or hard? 30. What is its form ? 31. What is its size? 32. What 
is its weight ? 33. Is it heavier in man or in woman ? - 34. Does its 
weight depend upon the intelligence of the person ? 35. Give ex- 
amples. 36. What can you say about the brains of idiots ? 37. 
Into what parts can the brain be divided ? 38. Where is the cere- 



182 

brum? 39. What are the hemispheres? 40. What can you say 
about the surface of the cerebrum ? 41. What is peculiar about the 
surface of the cerebrum in very intelligent persons ? 42. How is it 
different in the lower animals ? 43. What is the color of the cere- 
brum on the exterior ? 44. What is the color of the interior ? 45. 
Of what does the gray matter consist ? 46. Of what does the white 
matter consist ? 47. Describe the cerebrum. 48. Describe the me- 
dulla. 49. Why is it very important ? 50. What is a nerve ? 51. 
Where are the cranial nerves ? 52. To what are they attached ? 53. 
Name the functions of the brain. 54. What is meant by doing 
things " by instinct ? " 55. Where does the will exist? 56. What 
is meant by memory ? 57. What is intelligence ? 58. What is rea- 
son? 59. What is judgment? 60. How can we train the brain? 
61. What is the spinal cord ? 62. How is it protected ? 63. What 
is meant by " breaking the neck?" 64. Of what is the spinal cord 
formed ? 65. How does it look inside ? 66. What are the spinal 
nerves ? 67. How many are there ? 68. How do they leave the spi- 
nal cord ? 69. What two kinds of nerves are there ? 70. What are 
the functions of the spinal cord ? 71. What is reflex action ? 72. 
Give an example of reflex action. 73. Of what use is reflex action ? 
74. What is sleep? 75. How must the brain be rested ? 76. What 
is the average amount of sleep required for a man ? 77. How much 
for a child? 78. What are the uses of sleep? 79. What is the 
proper time for sleep ? 80. When should children go to bed ? 81. 
When should they rise? 82. What is nervousness? 83. What is 
nervousness due to ? 84. What is wakefulness ? 85. What are 
some of the most common causes ? 86. Is it natural for us to feel 
a little tired at night ? 87. Why can some persons who are idle all 
day long not sleep at night ? 88. How do coffee, tea, and tobacco 
act on the nervous system ? 89. What are narcotics ? 90. Which 
are used most frequently for producing sleep ? 91. What does 
chloral look like ? 92. Why do people take it ? 93. What effect 
does the "chloral habit" produce? 94. What does opium look 
like ? 95. Where does it come from ? 96. How is it obtained ? 
97. What is morphine ? 98. What is the morphine or the opium 
habit ? 99. Of what use is opium in sickness ? 100. Why do per- 
sons form the morphine or opium habit ? 101. What are the effects 
of this narcotic afterward ? 102. In what ways do they take opium 
or morphine ? 103. How do persons sometimes contract this hor- 



THE NERVOUS SYSTEM. 183 

rible habit ? 104. Is it a difficult habit to break off? 105. What 
are the effects of the habit upon the health ? 106. How does it 
end? 107. What is cocaine ? 108. Of what use is it? 109. W T hy 
do some people form the habit of taking cocaine ? 110. What 
effects does this have ? 111. How does the habit end very often ? 
112. What effect has alcohol upon the nervous system? 113. How 
is the brain affected in drunkenness ? 114. Name some of the dis- 
gusting actions of the drunkard. 115. How are the nerves affected ? 
116. What are the effects of repeated drunkenness ? 117. What is 
delirium tremens ? 118. What are the symptoms of delirium tre- 
mens ? 119. What effect has tobacco on the nervous system ? 120. 
What effect have coffee and tea on the nervous system ? 121. What 
is the sympathetic system of nerves ? 122. What is the function of 
the sympathetic system ? 123. What is its arrangement ? 124. To 
what parts is the sympathetic system distributed ? 



CHAPTER XL 

THE SENSES. 

383. There are certain organs in the body which add a great 
deal to our comfort and enjoyment and give us knowledge and 
pleasure. The functions of these organs are called the senses. 
There are five of them. 



1. 


Touch — The skin. 


2. 


Taste — The tongue. 


3. 


Smell — The nose: 


4. 


Sight— The eye. 


5. 


Hearing — The ear. 



384. Special Senses. — They are often called the special 
senses because each one has a special duty to perform and can- 
not be used for anything else ; as, for instance, our eyes can be 
used for seeing only. The skin is the only one of these organs 
which is necessary to life ; it is an organ of general rather than 
of special sense. 

THE SENSE OF TOUCH— THE SKIN. 

385. Thickness. — The skin forms a soft, elastic layer which 
covers the entire body. It is not of the same thickness all over. 
It is thick at certain places where the body is very much ex- 
posed or where there is much friction, as in the palms of the 
hands and the soles of the feet. In other places which are 
more protected, it is quite thin — for instance, the inner side of 
the arm. 

386. Uses of the Skin. — As has already been stated, the 
skin is necessary to life. In certain accidents, in which a per- 



THE SENSES. 185 

son has burnt or scalded himself severely, he may die because 
too much of the skin has been lost. There are four principal 
uses of the skin : 1, As a protection to the entire body ; 2, as 
the organ of sensation or feeling ; 3, to throw off water, salts, 
and poisonous matter from the body ; 4, to regulate the bodily 
warmth. 

387. The Skin as the Organ of Sensation or Feeling. 
— The nerves of sensation or feeling end in the skin by little 
knobs, which are the portions with which we feel the different 
sensations, such as heat, cold, smoothness, roughness, pain, etc. 
Some parts of the body are more sensitive than others — this is 
because they have a greater supply of these nerves. These 
same nerves also give rise to pain ; this is useful, for it protects 
the body ; it tells you when to be careful. If you are holding 
a lighted match in your fingers, you will drop it as soon as it 
burns down to your finger-tips because there is pain. If there 
were no pain to warn you, the ends of the fingers might have 
been burnt off before you were aware of it. With these nerves 
we are enabled to feel whether anything is smooth or rough, 
sharp or dull, cold or warm, soft or hard. The finger-tips are 
intended as the organs of touch. In the blind, the sense of 
touch becomes very much developed, and such persons can be 
trained to do wonderful things by means of the fingers. The 
books of the blind are printed with letters which are slightly 
raised ; it is marvellous how quickly they can spell the words 
by means of their fingers. 

388. Throwing off Water, Salts, and Poisonous Mat- 
ters. — This is a very important use of the skin. If an animal 
were to be covered with varnish so as to close all the pores, 
death would result in a short time. 

389. Regulating the Bodily Warmth. — The skin serves 
an important purpose in regulating the bodily warmth. It 
does this by increasing or diminishing the amount of perspira- 
tion, thus cooling the body in summer by permitting free per- 
spiration. 



186 



ANATOMY, PHYSIOLOGY, AND HYGIENE. 




390. Structure of the Skin. — The skin is formed of two 
layers (Fig. 82). The outside layer is called the scarf-skin, the 

deeper one the true skin. 

391. The scarf-skin is formed 
of a great many scales or flat 
cells covering each other ; these 
cells are being constantly rubbed 
away and cast off, and are then 
replaced by new ones. In taking 
a bath, for instance, it will be 
noticed that in drying a little of 
the skin comes off — this material 
is formed of the dead cells which 
are cast off. The scarf-skin of 
the scalp is often cast off in 
small scales which we call dan- 
druff. This thro wing-off of these 
scales from the skin of the body 
takes place all the time and is 
natural. In snakes the scarf- 
skin is thrown off in one piece and forms the very pretty 
tubes sometimes found in the woods. 

392. The true skin is the part which contains the blood-ves- 
sels and the nerves ; it also contains the roots of the hair, the 
perspiration-tubes, and the oil-tubes. If you burn yourself, a 
blister forms ; this separates the scarf-skin from the true skin ; 
if you lift up the blister, the red part you see underneath is 
the true skin. The true skin is not perfectly smooth, but has 
a number of small projections upon it ; but these do not ap- 
pear on the surface of the skin because the cells of the scarf- 
skin fill out the uneven places (Fig. 82). 

393. Color of the Skin.— The skin is colored differently 
in different parts of the body. It is darker, for instance, on 
the back of the hand than on the arm. Some persons have very 
light-colored skin and are said to have a fair complexion, and 



Fig. 82. — A Piece of Skin as Seen Under 
the Microscope, d. The layers of flat 
cells forming upper layer of the scarf- 
skin ; c, deeper layer of scarf-skin ; b, 
projections of true skin. 



THE SENSES. 187 

these usually have blonde hair. Others have dark complexions 
and usually have hair of a dark shade. In the negro, the skin 
is dark-brown. This difference in the color of the skin depends 
upon the amount of coloring matter which is found in the true 
skin. In white people there is very little of this ; in the negro 
there is a great deal of it, in the form of small dark-brown grains. 

394. If you look at the skin of the palms of the hands, you 
will see fine lines arranged in circles ; this you will see espe- 
cially at the finger-tips. If you examine these with a magnify- 
ing-glass it will be seen that these lines are raised ; it is here 
that the nerves of feeling end in great numbers. 

395. Attachments of the Skin. — Upon examining the 
skin, we find in it, or attached to it, certain parts : Perspira- 
tion-tubes, oil-tubes, hairs, and, in certain parts, nails. 

396. The Perspiration-tubes. — These are the small tubes 
in the skin, which give off the perspiration. There are a great 
many of them. Where they open upon the skin there is a 
small space called a pore. There are thousands of these pores 
in the space of every inch of the skin. This shows the necessity 
of keeping the body clean, so that these pores remain open, for 
otherwise the perspiration cannot escape as it should. The 
perspiration-tubes open upon the surface of the skin ; below, 
they commence by a series of windings in the deeper parts of 
the skin, as is shown in Fig. 83. 

397. The Perspiration. — Perspiration is constantly being 
given off from the body, day and night. Most of the time, 
especially when the weather is cool, we cannot see this — it is 
invisible, and hence it is called insensible perspiration. But 
if more than the usual amount is given off from the skin, the 
perspiration collects in drops and is called sensible perspira- 
tion. This occurs in summer and at other seasons of the year 
when we become over-heated or work hard. Perspiration 
consists largely of water ; in the water are dissolved certain 
mineral salts and certain poisonous matters which it is neces- 
sary for the body to cast off. 



188 



AND HYGIENE. 



398. Uses of the Perspiration. — It has just been stated 
that the perspiration takes from the body water, salts, and poison- 
ous matters. Even when . the weather is cold and perspiration 
is insensible, about a pint of water leaves the 
body daily by the skin ; in summer much 
more than this escapes. This will give an 
idea how many of these perspiration -tubes 
there must be and how active they must be. 
Perspiration is also very important because 
it cools off the body, as has already been de- 
scribed in the chapter on "The Heat of the 
Body." 

399. The Oil-tubes. — Besides the per- 
spiration-tubes, there are others which run 
through the skin and open on or near its 
surface, usually where there is hair. These 
tubes give off a certain oily substance which 
keeps the skin soft and movable ; without it 
fig. 83.— one of the the skin would get dry and cracked. This 

Perspiratory Tubes. ° ' " 

(Greatly magnified.) oily matter also serves to keep the hair glossy 
and soft ; and we find the greatest number of 
oil-tubes where there is hair. It is to remove 
the oily matter which has become stale that we 
need soap in washing. Sometimes there is too much of this oily 
matter and then the skin has a greasy look, such as we often 
see on the forehead and nose. Sometimes these oil- tubes be- 
come stopped up by a little dirt ; as a result the oily matter is 
kept in and we see a black spot on the nose or forehead ; this 
is often called a worm ; it is no worm, but is simply the oily 
matter which cannot escape because the opening of its tube 
has become clogged up. 

400. The Hair. — If a hair be examined it will be found 
that one end is pointed, while the other, which was attached 
to the skin, has a white knob ; this is its root, and it is through 
this that it is fastened to the skin (Fig. 84). The hair is not 




The tube is seen to 
pass through the en- 
tire thickness of the 
skin, through its dif- 
ferent layers. 



THE SENSES. 189 

solid but is a tube, and has a canal in its centre which is filled 
with a soft material. Deep in the skin there are small cup-like 
spaces into which the root of the hair fits and is attached. 
Hair differs very much in color, and this is because there is a 
difference in the amount of the coloring substance present in 
different cases. 

401. The Nails. — At the end of the fingers and toes are 
the nails. They are hard and horny and serve to protect the 
finger tips and give them firmness. In front they have no feel- 
ing and we may cut them without paining us. But further 




Fig. 84. — A Piece of Skin Cut Across, to Show the Way in which Hair is Attached to the 
Skin. (Highly magnified). There is seen to be a depression in the skin into which the 
hair dips. Below, the round, expanded extremity or root of the hair is seen. 

back they are very firmly attached to the back of the finger 
and here they are very sensitive. 

402. Care of the Skin. — You will now appreciate how im- 
portant the skin is, and why it is necessary to keep it in good 
condition. Cleanliness is next to Godliness is an old saying ; 
if you wish to be healthy you must be clean. Dirt is, as a 
rule, a sign of ignorance ; and those nations are usually the 
dirtiest which are the most backward in civilization. On the 
other hand, the more civilized people are, the cleaner do they 
keep themselves. There are few things that cause so much dis- 
ease as uncleanliness and filth. 

403. The Results of Uncleanliness and Filth.— When- 
ever you read of outbreaks of cholera and such diseases you 



190 ANATOMY, PHYSIOLOGY, AND HYGIENE. 

will always find that they occur in parts of cities which are 
overcrowded and filthy ; this was shown in the last outbreak 
of this disease, many years ago, in New York. It is easy to 
understand why this should be so. The pores of the skin are 
the openings by which the body gets rid of waste materials, 
just as the sewer-pipes of a city carry off the refuse. Suppose 
the sewer becomes stopped up in a large city ; what trouble 
this causes ! What dirt ! What a stench ! In the same way, 
when we allow the dirt to cover the pores of our skin, the 
poisonous materials cannot escape, and the body suffers. In 
taking proper care of the skin it is necessary to pay attention 
to bathing, to our clothing, to exercise, and to avoid using pow- 
der or any like substance upon the skin. 

404. Bathing. — It is not sufficient to wash the hands and 
face daily ; we should wash off the entire body at least once a 
week. If you shake out some of your underclothing at night, 
you will find a great many small white flakes fall to the ground. 
They represent the uppermost layer of the skin which is con- 
stantly being cast off in these small particles and replaced by 
the deeper layers. The entire body is covered with these 
scales, and it is necessary to remove them often. Some fall off 
by themselves, but others must be removed by soap and water. 
Consequently, at least once a week we should take a warm 
bath, and use soap in it, for this removes the stale, oily matter 
also. 

405. Cold Baths. — Besides the warm bath for cleanliness' 
sake, we should take cold baths, especially in summer, because 
they are refreshing and strengthening. After taking a cold 
bath it is well to rub the body with a coarse towel so as to 
make the skin glow and tingle ; this causes the blood to circu- 
late faster, and increases our strength and appetite. It is in- 
jurious to remain in a cold bath until you begin to shiver. As 
soon as you begin to feel chilly you should go out. Many per- 
sons are harmed by cold bathing because they remain in the 
water for too long a time. Some persons are naturally weak, 



THE SENSES. 191 

and when they take a cold bath they are not able to withstand 
its effects, so that even though they rub the body afterward 
they still feel cold and chilly ; this is a sign that they are un- 
able to endure cold bathing. Such people should be content 
to simply sponge off the body with cold water, besides taking 
a warm bath about once a week for the purpose of cleansing 
the body. Never bathe directly after a meal ; wait two or three 
hours. If you are overheated and perspire freely, it is better 
to wait until you are somewhat cooled off before you go into 
cold water. Always wet the entire head as well as the rest of the 
body when bathing. 

406. The Turkish and the Russian Bath. — Probably 
all of you have heard of the Turkish bath and the Eussian bath. 
In the Turkish bath, the person is kept in a room with very hot 
air until he perspires freely ; he is then scrubbed with soap 
and water ; then he plunges into a cold water bath ; next 
his skin is rubbed and his muscles kneaded by men who are 
employed for this purpose ; this causes the blood to flow 
faster ; then the person rests himself thoroughly before going 
out into the air. The Russian bath is similar, the only differ- 
ence being that the room is filled with steam instead of 
with hot air, to make the person perspire freely. These 
baths are good for grown people, but are not suitable for 
children. 

407. Clothing.— Something has already been said about 
proper clothing in the chapter on "The Heat of the Body," so 
that little need be added here : We should change undercloth- 
ing frequently ; it is a healthy practice to take off all our un- 
derclothing at night and allow it to hang up and be thoroughly 
aired before putting on again the next morning. 

408. Exercise helps to keep the skin in good condition, by 
making us perspire more freely, and in this way keeping the 
pores open. It also causes the blood to circulate through the 
skin more rapidly — this gives us the delightful feeling of 
warmth after exercising. 



192 ANATOMY, PHYSIOLOGY, AND HYGIENE. 

409. Cosmetics. — The use of powders and like substances 
to the skin is very injurious. These substances, which are 
called cosmetics, stop up the pores and make the skin rough 
and ugly. Besides, many of them are poisonous, and this 
poison may get into the blood through the skin and may 
poison the body. Powdering the face is not done by the better 
class of people. 

410. Care of the Hair. — The hair should be combed and 
brushed every morning. Every few weeks it will be necessary 
to wash it with soap and water. The oil-tubes of the scalp 
usually supply enough oily matter to keep the hair glossy ; 
hence the practice of putting oil or grease on the hair is not 
only very vulgar and nasty but it is unnecessary. Crimping the 
hair by hot irons destroys the hair and makes it fall out. Hair- 
dyes are injurious ; nearly all of them are made of deadly poisons, 
and these may get into the blood and poison the entire body. 

411. Care of the Nails. — The nails should be cut with 

scissors at regular intervals. The 
finger-nails should not be bitten 
off. The nails should not be cut 
too close or else the finger-tips 
and the ends of the toes will be- 

fig. 85.— Proper and improper Method come sore. Many persons have 

of Trimming the Toe nails. The figure ■ . ■,, xl -. . , 

to the left exhibits the proper method— SOl'e toeS, especially the Dig toe, 
cut off squarely : that to the right the -i xi i l l i_i *i 

improper method - cut off round and because they do not cut the nail 

properly; it should be cut 
straight across and not rounded and short (Fig. 85). Hangnails 
often result from biting the nails or keeping the fingers in the 
mouth. 




THE SENSES. 193 

SYNOPSIS. 
The Skin: 

1. Thickness — Varies in different parts of body. 

2. Uses: 

a. Protection. 

b. Organ of sensation or feeling : 

1. Acuteness varies in different parts of body. 

2. Greatest at finger-tips. 

3. May be developed, as in the blind. 

4. Depends on the nerves of sensation, ending in the 
skin by small knobs. 

c. To throw off water, salts, and poisonous matters from 
the body. 

d. To regulate the bodily warmth. 

3. Structure : 

a. Scarf-skin on the outside. 

b. True skin beneath. 

4. Color: 

a. Varies in different parts of body. 

b. Varies in different races. 

c. Depends on the amount of brown coloring matter ex- 
isting in the true skin. 

5. Attachments : 

a. Perspiration-tubes — Openings called pores ; necessity 
for keeping open ; perspiration, sensible and insensible ; 
removes matters from body and cools body. 

b. Oil-tubes — Necessity for using soap to remove stale 
oily matter. 

c. Hair — Root and point ; hollow ; color varies ; should 
be combed and brushed daily ; should be washed every few 
weeks ; no oil or dyes. 

d. Nails— Should be cut regularly, not bitten off; cut 
across square. 

6. Care of Skin : 

a. Cleanliness. 

b. Bathing : 

1. Warm bath and soap for cleanliness. 

2. Cold bath, refreshing. 
13 



194 ANATOMY, PHYSIOLOGY, AND HYGIENE. 

3. Turkish bath. 

4. Russian bath. 

5. No bathing directly after meals. 

6. No bathing when overheated. 

7. "Wet head as well as rest of body. 

c. Clothing — Necessity for changing underclothes fre- 
quently. 

d. Exercise. 

e. Cosmetics — To be avoided. 



QUESTIONS. 

1. Name the special senses. 2. Is the skin of the same thickness 
throughout the body ? 3. At what points is it the thickest ? 4. What 
are the uses of the skin? 5. Is it necessary to life? 6. How is 
this proven ? 7. Of what service is pain ? 8. Of what use are the 
nerves of feeling ? 9. What parts of the body are intended espe- 
cially for feeling ? 10. What is peculiar of the touch of the blind ? 
11. What is discharged from the body by means of the skin? 12. 
What effect has the skin ujoon the bodily warmth? 13. Is the color 
of the skin always the same ? 14. Upon what does the color of the 
skin in the negro depend? 15. Of how many layers is the skin 
formed? 16. What are these layers called? 17. Of what is the 
scarf-skin formed? 18. What becomes of the scales which form the 
scarf-skin? 19. What is " dandruff?" 20. Describe the true skin. 
21. How do the two layers of the skin become separated in slight 
burns ? 22. Describe the perspiration-tubes. 23. What are the 
pores? 24. What is "insensible" perspiration? 25. What is "sensi- 
ble " perspiration ? 26. What are the uses of perspiration ? 27. What 
does the perspiration remove from the body? 28. About how much 
perspiration leaves the body every day ? 29. How does perspiration 
cool off the body? 30. What appearance does the skin of the finger- 
tips present ? 31. What other tubes are there besides the perspira- 
tion-tubes ? 32. Of what use is the matter which the oil-tubes pro- 
duce ? 33. What happens when the oil-tubes get stopped up ? 34. 
Why does the skin of the nose and forehead sometimes have a 
greasy look ? 35. Describe a hair. 36. How is hair attached to the 
skin? 37. Of what use are the nails? 38. Why is cleanliness so 
very important? 39. Of what is dirt a sign in regard to civilization? 



THE SENSES. 



195 



40. What effect upon the health has filth? 41. Why is filth so bad 
for the health ? 42. How often should the entire body be washed ? 
43. Why should the entire body be washed frequently with soap and 
warm water? 44. What are the effects of a cold bath? 45. What 
should we do to make the circulation more brisk after a cold bath ? 

46. What is the sign that you have been in a cold bath long enough ? 

47. Is it well to bathe directly after a meal ? 48. What other pre- 
cautions should you take when bathing ? 49. Explain the Turkish 
and the Eussian bath. 50. Should we wear the same underclothing at 
night that we have worn during the day ? 51. How does exercise 
affect the skin? 52. What are " cosmetics?" 53. What effect have 
they upon the skin? 54. What should be done to the hair? 55. 
What can you say about the practice of putting oil or grease upon 
the hair ? 56. What are most hair-dyes made of ? 57. How should 
the nails be cut ? 



412. 

smell. 



THE NOSE— THE SENSE OF SMELL. 

Functions. — The nose is the organ with which we 
It is also the part through which the air is drawn. The 



Smell .... 



food 




Fig. 86.— Diagram Exhibiting the Channels by which Smell, Air and Food Reach the In- 
terior of the Body. 

lower part of the nose represents a passage for breathing, the 
upper portion is the part devoted to the sense of smell (Fig. 86). 



196 ANATOMY, PHYSIOLOGY, AND HYGIENE. 

413. The Breathing Channel and the Smelling Chan- 
nel. — When we breathe we draw the air backward through the 
lower part of the nose ; this part of the nose runs horizontally- 
backward, and behind joins the throat ; so that if a fluid is 
poured into the nose it will run into the throat. When we 
smell, we draw the air upward, because we want the odor to 
ascend to where the nerves of smell are. 

414. Parts of the Nose. — The nose is formed of bones 
and of gristle. The hard part on the outside, where you usu- 
ally see people wearing their eye-glasses, is formed of two 
small bones and is called the bridge of the nose. In looking 
into the nose we find that it is divided into two halves. The 
openings in front are called the nostrils. In the interior of 
the nose, on each side, are found three shelves of bone covered 
by a soft membrane ; beneath each shelf is a passage-way 
which runs from the front to the back of the nose. 

415. The Nerves of Smell. —In the membrane which 
covers the two upper shelves just described, are found numer- 
ous nerves ; they are the nerves of smell. By consulting Fig. 
87, it will be seen that the brain lies immediately above the 
nose. These nerves of smell come in bunches from the brain, 
and descend into the nose. Although we are in the habit of 
saying that we smell with the nose, it would be more correct, 
strictly speaking, to say that we smell with the front part of 
the brain. The nerves of smell merely serve to carry the odors 
to the brain. This is proven by the fact that there is a loss of 
the sense of smell if the front part of the brain be injured or 
diseased ; there is now no longer any smell, even though the 
nerves of smell may still be present. 

416. The Sense of Smell in the Lower Animals. — 
Many of the lower animals have a much more acute sense of 
smell than man. Dogs and cats, for instance, can smell the 
faintest odors at great distances. In hunting-dogs the sense 
of smell is extraordinarily acute ; they can smell game miles 
away and in this way are valuable in hunting ; this is spoken 



THE SENSES. 



197 



of as " scenting the game." Before the civil war, bloodhounds 
were employed to track runaway slaves, and they were able to 
do this, owing to the acuteness of their sense of smell, when 
the fugitives were many miles in the lead. 

417. Cold in the Head. — Nearly everyone has caught cold 
at some time or other. When we catch cold it may settle in 
any part of the body ; it may attack the lungs, or the stomach, 
or some other organ. When the cold settles in our head we 




Fig. 87.— View of the Interior of the Nose, showing the Nerves of Smell Descending into 
the Nose from the Brain, in the Form of a Bunch. 



usually feel it principally in the nose and throat ; we often get 
a sore throat and our nose feels stopped up so that we cannot 
smell, and we cannot breathe through it ; it feels this way be- 
cause there is too much blood in it. 

418. Cold in the head is most often due to sitting or stand- 
ing in the draught, or to going suddenly into the cool air when 
we are overheated, without putting on some additional cloth- 
ing. Very often we know that we have been imprudent in this 
way and can feel the cold coming on, and then a mustard foot- 
bath may prevent it. 



198 ANATOMY, PHYSIOLOGY, AND HYGIENE. 

419. Use of the Sense of Smell. — With the sense of 
smell we are able to enjoy agreeable odors. But what is im- 
portant is, that we are also able to smell bad odors ; this pro- 
tects the body by informing us of the whereabouts of obnox- 
ious things that should be avoided, and especially of impure 
air. It enables us to select the proper food, and to refuse that 
which is unfit to eat. It often protects our bodies and homes 
by enabling us to smell smoke and in this way to discover the 
existence of a fire. 

420. Sweet Scents. — To smell the sweet odors which 
flowers give off, is very agreeable. Odors are given off by the 
oils existing in the flowers of plants ; these oils are extracted 
from the flowers and this is then called perfume. Many per- 
sons use this perfume to put upon their handkerchiefs and 
clothes so that they shall smell sweet ; but the nicest kind of 
people do not use perfumes as a rule. If you always keep the 
body clean and brush your teeth often you will not need any 
perfume ; for if the body is clean, it always smells sweet. 
Soap and water are better than perfume to tidy people. 



SYNOPSIS. 

The Nose : 

1. Parts: 

(1.) Two bones forming "bridge." 

(2.) Gristle. 

(3. ) Three shelves running from front to rear. 

(4.) Shelves covered by soft membrane. 

(5.) Membrane of upper two shelves supplied with 

(6.) Nerves of smell which descend in a bunch from brain. 

2. Function : 

(1.) Lower passage for air. 

(2.) Upper part for sense of smell. 

a. Great acuteness in some of lower animals. 

b. Blunted in cold in head. 

c. Use — To protect us from impure air and im- 
proper food. 



THE SENSES. 199 



QUESTIONS. 

1. What are the uses of the nose ? 2. Which part of the nose 
serves for breathing ? 3. Which part is used for smelling ? 4. Of 
what is the nose formed ? 5. Where is the bridge of the nose ? 6. 
What are the nostrils ? 7. What do we find in the inside of the 
nose ? 8. Where are the nerves of smell ? 9. Where do they come 
from? 10. How is the nose connected with the throat? 11. Where 
do we find the more acute sense of smell, in man or in the lower 
animals? 12. Give an example. 13. What is meant by a " cold in 
the head ? " 14. What is this often caused by ? 15. What are the 
uses of the sense of smell ? 16. What parts of plants usually give 
off the sweet scents ? 17. What can you say about the habit of 
using perfume upon the handkerchief or clothing. 



THE TONGUE AND THE SENSE OF TASTE. 

The tongue is the organ with which we taste our food. 

421. Structure of the Tongue. — This organ consists 
almost entirely of muscle tissue. Its under surface is smooth. 
Its upper surface is very rough. This roughness is due to a 
large number of small projections. These can be seen better 
in the tongues of the lower animals than in man, and serve two 
purposes : First, they are the parts which give us taste ; the 
nerves of taste end in rounded extremities in these elevations. 
The other use is to feel the food in our mouth and to discover 
whether it is chewed sufficiently fine, and is mixed enough with 
the saliva, before it is swallowed. The lower animals, such as 
dogs and cats, are enabled to scrape off bones by means of 
these projections. 

422. Uses of the Tongue. — The tongue's functions are : 
(1) as the organ of taste ; (2) to revolve the food in the mouth, 
to mix it with the saliva, and to assist in swallowing ; and (3) 
in speaking. The importance of the sense of taste need not be 



200 



ANATOMY, PHYSIOLOGY, AND HYGIENE. 



pointed out especially ; it enables us to choose our food and 
to avoid that which is unfit to eat ; it prevents us from eating 
improper food ; it increases the appetite and makes us enjoy 
our meals when the food is to our liking. Besides turning the 
food about in the mouth and mixing it with saliva, the tongue 




—The Human Tongue. 



separates hard portions of the food, such as seeds and shells, 
and it also assists in swallowing. Finally, the tongue assists 
in speaking. 

423. Abuse of the Sense of Taste. — The sense of taste 
adds a great deal to our enjoyment ; it is necessary, however, 
to prevent it from enjoying too many liberties, otherwise we 



THE SENSES. 201 

will be eating too much, become gluttons, and suffer in health. 
In selecting our meals, we are guided by what is wholesome, 
nourishing, and digestible. 

SYNOPSIS. 

The Tongue. 
Structure — 

1. Formed of muscle-tissue. 

2. Smooth on under surface. 

3. Kough on upper surface, due to 

4. Small projections which serve to 

a. Feel food to see if properly chewed. 

b. Taste with, since nerves of taste end here. 
Uses — 

1. Organ of taste. 

2. To revolve food in mouth, mix it with saliva, remove hard 

portions, and assist in swallowing. 

3. To assist in speaking. 

QUESTIONS. 

1. Describe the tongue. 2. Of what kind of tissue is it made 
up? 3. Which surface is rough? 4. What is this roughness due 
to ? 5. Of what use are these small elevations ? 6. What are the 
uses of the tongue ? 7. What are the uses of the sense of taste ? 
8. How might we abuse the sense of taste ? 



THE EYE AND THE SENSE OP SIGHT. 

424. Protections to the Eye. — The eye is one of the 

most delicate organs in the body. It is placed in the large 
opening in the skull found just below the forehead, on each 
side of the nose, called the orbit. This affords it considera- 
ble protection. Besides this, it is also protected by the eye- 
brows, eyelids, and eyelashes. In the orbit the eye rests upon 
a soft cushion of fat. 



202 



425. The Eyelids.— These serve to protect the eyes by 
their quick movement in closing, thus keeping out dust. They 
keep out the light when too strong, or during sleep. 

426. The Eyebrows and Eyelashes.— These keep the 
perspiration from rolling into the eyes, and keep out dust. 
They should never be cut, for this will not cause them to grow 
any longer and spoils them by making them thick and stiff. 



End of choroid coat in front. . 

Space behind iris 

Membrane supporting the lens 

Cornea 

Aqueous humor 

Lens 

Iris 

Space behind iris . 

End of choroid coat in front . . 




Fig. 89.— The Human Eye (Cut Across and Enlarged), Showing Its Different Parts and 

the Interior. 



427. Parts of the Eye. — The eye is spherical in shape, 
measuring about an inch in diameter. Its front portion is per- 
fectly transparent, and is called the cornea. But behind the 
cornea, which forms about one-fifth of the circumference of the 
eyeball, it is opaque and white, and can be separated into three 
layers, or coats. The outermost layer is hard and strong, and 
it preserves the form of the eyeball ; it is called the white of 
the eye, or the sclerotic coat. The middle layer is dark-colored, 
and is called the choroid coat. The inner layer is called the 



THE SENSES. 203 

retina. It is of great importance, because the nerve of the eye 
sends its branches to it, and it is the portion of the eye with 
which we see (Fig. 89). 

428. Looking into the eye, we see in the centre a black spot 
which is called the pupil ; it is a round opening in a mem- 
brane which acts as a partition to this part of the eye. This 
membrane is a colored ring which surrounds the pupil and is 
really a curtain hanging behind the clear part of the eye ; it is 
called the iris. 

429. Behind this curtain, the iris, is a round transparent 
body, about the size of a cherry-pit, which is called the lens. 
It is perfectly clear and its shape is like that of a small magni- 
fying-glass ; but it is softer — like a hard jelly. It is supported 
behind the iris, just where the transparent part of the eye 
joins the opaque portion, by a delicate membrane, and is flat- 
tened somewhat in front and behind. 

430. The interior of the eye is filled with fluid. Just be- 
hind the cornea, extending to the lens, is a space which is 
filled with a watery fluid called the aqueous humor. The 
rest of the eye-ball (behind the lens) is filled with a clear 
substance like white jelly, called the glassy body or vitreous 
humor. 

431. The Iris. — It has just been explained that this is a 
sort of curtain placed in front of the lens of the eye. There is 
a round opening in the centre, by which light is admitted to 
the eye ; this is the pupil. The pupil changes its size very often. 
When we look at anything in the distance the pupil becomes 
large ; when we look at objects close by it becomes very small. 
The pupil also regulates the amount of light which should 
enter the eye. In going into a bright light, as for instance into 
the sun, the pupil becomes very small ; if it did not do so the 
light would be too bright and would injure the eye. It is very 
dangerous to the eye to try to look at the sun. In the twilight, 
when the light is dim, you will notice that the pupil becomes 
very large. 



204 ANATOMY, PHYSIOLOGY, AND HYGIENE. 

432. The Muscles of the Eye.— It is wonderful how 
rapidly the eyes move ; this is necessary to protect the body. 
The rapid motion of the eyes is also necessary so that they 
can act together. If you were to press upon one eye so that 
it could not move, and then were to move the other, every- 
thing would look double ; so that the two eyes must move to- 
gether if we want to see singly and plainly. There are six 
small muscles (Fig. 90) attached to each eye, which make its 
movements so rapid. Sometimes one of these muscles does 
not act as well as it should ; then the eye turns in all the time 




Fig. 90.— The Muscles Attached to the Eyeball and to the Upper Lid. 



or constantly looks outward ; the person then is cross-eyed or 
squints. Some children are born this way and it is not right 
to make fun of them. Sometimes children turn their eyes so 
as to imitate cross-eyed persons ; this habit is very injurious. 

433. How We See. — It may seem strange to say that we 
really see with the brain, but such is the case. Of course the 
eyes are necessary, and without them we would be blind ; but 
the brain is also necessary for sight. If a certain part of the 
brain be injured we cannot see, even though our eyes remain 
as clear and bright as they were before. 

434. Resemblance of the Eye to a Photographer's 
Camera. — The eye resembles the box which the photographer 
uses to take pictures, and which is called a camera. Let us see 
how it resembles the photographer's camera : In the first place 



THE SENSES. 205 

the photographer cannot take a picture in the dark, nor can 
we see in the dark. Secondly, in the front of the camera 
there is a lens of glass ; we also have a lens, though it is of 
course not of glass, but of a better and softer material. Again, 
in the back of the photographer's camera is a glass plate, upon 
which the picture falls and is taken ; in the same way in our 
eyes the retina serves as a plate upon which to take the picture. 
Anything which we see forms an image upon the retina. This 
image only lasts a short time ; but long enough for us to see 
it. Finally, you have probably noticed how the photographer 
puts a black cloth over his head and the back of the camera so 
as to keep it dark ; the middle, colored coat of the eye — the 
choroid — serves to darken the inside of the eye. 

435. The Nerve of the Eye.— Connected with the back 
of the eye is a portion resembling a cord, which passes to the 
brain ; this is the optic nerve or nerve of the eye. It is the 
nerve which connects the eye with the portion of the brain 
used in seeing. On arriving at the eye the nerve spreads out 
in the interior of this organ and forms the innermost layer, 
which is called the retina. By looking into the interior of the 
eye with an instrument, the oculist can see this layer. It is 
shown in Fig. 91 ; the central spot is where the nerve enters 
the eye ; at this point blood-vessels also enter the eye and then 
divide and spread out in a very pretty manner. 

436. Blindness. — If the optic nerves of both sides become 
diseased, or both retinse become changed, the person may be- 
come totally blind, even though the eye appears perfectly 
healthy on the outside. These nerves carry the sight from the 
eye to the brain, with which seeing is really done. 

437. Images. — The word image has been used and will re- 
quire some explanation. If you look into a mirror you will see 
your face — this is an image of your face. The light strikes 
your face and from it passes to the mirror ; there it forms an 
image ; from this image the light passes into the eye and forms 
another image upon the retina, which we see. 



206 ANATOMY, PHYSIOLOGY, AND HYGIENE. 

438. The Tears. — The eye is constantly kept moist by be- 
ing bathed with the tears. At the outer part of each eye, be- 




Fig. 91.— A View of the Interior of the Eye, as Seen with the Oculist's Instrument. 




Fig. 92.— The Lachrymal Gland, Sac, and Duct. 



tween it and the bone forming the roof of the orbit, is a small 
body called the lachrymal gland (Fig. 92), meaning tear-gland ; 
this body is constantly pouring the tears over the eye so as to 



THE SENSES. 207 

keep it moist ; even during sleep this takes place, though there 
is then much less produced. "When we are awake the eye is mov- 
ing constantly and this spreads the tears over the eyeballs. After 
the tears have moistened the eye, they are collected again and 
escape into the nose. If you look at your lids you will notice 
near the inner corner of the eye, a small spot about the size of 
a pin's point ; there is one of these on the lower lid and one on 
the upper ; the tears pass into these openings and then into a 
small bag near the nose, called the tear-sac ; then they are car- 
ried down into the nose by a tube called the tear-duct or nasal 
duct (Fig. 92). You have noticed how the nose runs after cry- 
ing ; this is because there is so much more of this fluid dis- 
charged into the tear-duct. If anything gets into the eye, the 
lachrymal gland produces more of the tears and they flood this 
organ until the intruding body is swept away. If we become 
very sad or very angry, tears become very abundant. 

439. Care of the Eyes. — There is no organ in the body 
which contributes so much to our comfort, our enjoyment, and 
our knowledge, as does the eye. And yet the eye is constantly 
being misused. If you have good eyesight you should take 
care of your eyes so that it does not get bad ; if your eyesight 
has already become bad you should see that it does not get any 
worse. Some of the most common rules for the care of the 
eyesight are the following : 

440. After having read a long time, it is well to stop and 
rest the eyes ; the eyes, like any other part of the body, cannot 
be used continuously. It is quite natural that the eyes should 
feel tired and begin to pain after we have used them a long 
time ; this is nature's sign that they need rest. 

441. Never read in a poor light. You may be finishing a 
chapter in your book and you notice that it is beginning to get 
dark ; yet you do not stop until you get to the end of the chap- 
ter even though you strain your eyes. This is wrong and the 
eyes suffer for it. 

442. Never read very fine print if you can help it. 



208 ANATOMY, PHYSIOLOGY, AND HYGIENE. 

443. In reading, have the light come over your shoulder and 
thus fall upon the book or paper without going directly into 
your eyes. It is better to sit with your back to the window 
and thus have the light come over your shoulder. This pre- 
caution is especially useful at night, for the glare of the gas- 
light or lamp is very tiring to the eyes ; while if the light is 
behind you and falls over your shoulder there is just as much 
light upon your book or paper and yet the eyes are spared the 
brightness. 

444. Never read while lying upon the bach You cannot read 
comfortably in this position and you have to strain the eyes 
so that it is very tiring. If for any reason you must read lying 
down, do so with the shoulders and head raised into a half- 
sitting position. 

445. There may be some excuse for business men reading in 
the cars, for often this may be the only time they have to read 
the daily papers. But there is no reason why children should 
do this. It is injurious, in the first place, because the light is 
usually poor, but chiefly, because the constant jolting of the 
car makes the page unsteady and requires a constant strain 
upon the eyes to keep the place. 

446. Never use the water which another person has used to wash 
their face in for a similar purpose. Never use a towel for wip- 
ing your face, which another person has had to his face, unless 
this person is one of your family and you know he has no eye 
disease. There is a disease of the eyelids which is called gran- 
ular lids which is very contagious ; many children contract it 
in school by using the towel which another child who had the 
disease, has used. 

447. Do not stoop when you read, but raise the book so that 
you can hold the head erect. 

448. Weak Sight. — Some persons are born with weak eyes 
— that is, they do not see as well as other people and have to 
wear glasses. Some of these people are called near-sighted, 
others are called far-sighted. If the doctor advises you to wear 



THE SENSES. 209 

glasses you should not be ashamed to do so. Only vain per- 
sons object to wearing glasses, when they are necessary. 

449. Old Sight.— After persons get about forty years old 
they can still see well in looking at things far away ; but they 
need glasses for looking at near objects. 



SYNOPSIS. 

The Eye : 

1. Protections : 

a. Surrounded by bony " orbit." 

b. Rests on cushion of fat. 

c. Eyebrows — Keep off perspiration. 

d. Eyelids. I Keep Qut ^^ ^^^ and perS pi ra ti n. 

e. Eyelashes. ) 

2. Parts: 

a. Coats : 

1. Opaque part behind. 

a. Sclerotic — Outer, white, dense. 

b. Choroid — Middle, colored, brown. 

c. Retina — Inner, composed of nerve -tissue. 

2. Transparent part in front — Cornea. 

b. Iris— Curtain to keep out light ; in centre is 

c. Pupil — Size changes. 

d. Lens. 

e. Fluids : 

1. Aqueous humor. 

2. Vitreous humor. 

/. Muscles — Six small ones attached to eye, to move it 
in all directions. 

g. Nerve — Attached behind and passing to brain, with 
which we really see. 

h. Lachrymal duct — Near the eye, gives off the tears, 
which keep the eyeball moist, collected by tear-sac and es- 
cape by tear-duct into nose. 
Care of the Eye : 

1. Requires rest when used for long time. 

2. Good light in reading. 

3. Injurious to read very fine print. 

14 



210 ANATOMY, PHYSIOLOGY, AND HYGIENE. 

4. Light should come from behind — over shoulder. 

5. Not well to read while lying down. 

6. Not well to read while riding. in cars. 

7. Eisk of contracting eye disease in using towels or water 
that other people have used, to eyes. 

8. In reading, sit erect. 

9. "Weak sight requires glasses. 

10. Old sight (after forty) requires glasses. 

QUESTIONS. 

1. In what are the eyes placed? 2. How are the eyes protected ? 
3. "What do the eyelids do ? 4. Of what use are the eyebrows and 
eyelashes ? 5. Why should we not cut the eyelashes or the eye- 
brows ? 6. What is the shape of the eye ? 7. What is the cornea ? 
8. How many layers has the back part of the eye? 9. What is the 
back part called ? 10. Which is the most important of these three 
layers? 11. What is the pupil ? 12. What is the iris? 13. What 
is the lens ? 14. With what is the interior of the eye filled ? 15. 
What two fluids do we have in the eye ? 16. Is the pupil always of 
the same size? 17. When does it become large? 18. When does 
it become small ? 19. Of what use is the pupil ? 20. How many 
muscles are there to each eye ? 21. Of what use are these muscles ? 
22. What is the cause of cross-eyes ? 23. With what part of the 
body do we really see, the eye or the brain? 24. How is this 
proven ? 25. What instrument may our eye be compared with ? 
26. Explain in what ways our eye resembles the photographer's 
box ? 27. Where is the nerve of the eye ? 28. What does it do ? 
29. What do we mean by an image ? 30. How is the eye kept 
moist ? 31. Where is the body which produces the tears ? 32. 
What is it called ? 33. How are the tears collected again ? 34. 
What becomes of them ? 35. Where is the tear-sac ? 36. Where is 
the tear-duct ? 37. What causes the tears to flow more than usual ? 
38. Why should we stop after we have read a long time ? 39. What 
does a tired feeling or pain in the eye after reading mean ? 40. 
What sort of light should be avoided ? 41. Where should the light 
come from when you read ? 42. Should it come from the front ? 
43. Why not? 44. Can a person read lying down, without injury 
to his eyes ? 45. Why not ? 46. Why should we not read on the 



THE SENSES. 



211 



cars ? 47. Why should we not use towels that other persons have 
used to their faces? 48. What disease of the eyelids may be con- 
tracted in this way ? 49. What position should you take when you 
read ? 50. What is meant by weak sight ? 51. After what age do 
people need glasses for reading ? 



THE EAR— THE SENSE OF HEARING. 



450. Like the eye, the ear is an organ which adds very 
much to our comfort, pleasure, and knowledge. 

451. Parts of the Ear. — The ear is divided into three 
parts : An outer, a middle, and an inner. 

452. The Outer Ear is the portion which you see at the 
side of the head. It is expanded and 
formed of gristle, covered with skin. 
Its shape is not only ornamental, but 
useful, for it serves to collect the 
sound and lead it into the deeper 
parts of the ear. As a rule, we 
cannot move the ears ; but in the 
lower animals, the ear can be moved 
in all directions and in this way 
these animals tell where the sound 
comes from. From this outer part 
of the ear there is a canal about an 
inch long which leads to the next 
part of the ear, the middle ear. In 
this canal is usually found a little 
yellowish substance, which we call 
ear-wax ; this serves to keep the 

canal soft and moist and to keep out insects, for the latter dis- 
like this wax. 

453. The Middle Ear. — The middle part of the ear con- 
tains the so-called drum ; it is only about half an inch across. 




The Outer Ear. 



212 



ANATOMY, PHYSIOLOGY, AND HYGIENE. 



It is at the bottom of the canal which leads from the outer ear. 
Between the two a sheet of membrane is stretched which is 
called the drum-membrane. In the middle ear itself there is 
nothing but three small bones which are joined one to the other 
so as to form a small chain. One end of this chain is fastened 
to the drum-membrane and the other to the inner ear, so that 
these bones connect the outer ear with the inner ear. 




Fig. 94.— The Different Parts of the Organ of Hearing. 1, The outer ear ; 2, the canal 
leading from the outer to the middle ear ; 3, temporal bone ; 4, Eustachian tube ; 5, nerve 
of hearing ; 6, the internal ear. 



454. Bones of the Ear. — These bones are shown in Fig. 
95 ; they are very interesting. They are named, according to 
their shape, the hammer, the anvil, and the stirrup. 

455. Connection Between the Ear and the Throat- 

— Perhaps you may have noticed that sometimes when you 
blew your nose hard there was a stuffed feeling in the ears ; or 
that when your throat was sore your ears were also affected. 
Sometimes, too, when you swallow you feel something in your 



THE SENSES. 



213 



ear. This is because there is a tube which runs from the 
throat to the middle ear. It is very important that this tube 
remain open, for otherwise air cannot enter the middle ear as 
it should and we do not hear well. This tube is called the 
Eustachian tube, after the physician who first described it. 

456. The Internal Ear. — This part of the ear is placed 
very deeply in the bone. There are several circular passage- 
ways and a winding passage like a staircase hollowed out of 
the bone, and in these the inner ear is contained. In these 
circular canals we find a delicate membrane and a fluid on 





Fig. 95.— The Small Bones of the Ear. A, 
The hammer ; B, the anvil ; C, the stirrup. 



FIG. 96.— The Internal Ear. 



each side of it. The arrangements in the internal ear are very 
intricate. 

457. The Nerve of Hearing. — The nerve of hearing is at- 
tached to the internal ear and from this part it passes to the 
brain ; it therefore conducts the sound to the brain just as the 
optic nerve conducts sight to the brain. 

458. Sound.— Before studying how we hear, it is necessary 
to understand how sound is produced. Sound is produced 
whenever the air is made to vibrate — that is, whenever the air 
is put into motion resembling waves. You will understand 
this better if you think for a moment of the water : suppose 
when a pond is quiet, you throw in a stone ; this causes a mo- 



214 ANATOMY, PHYSIOLOGY, AND HYGIENE. 

tion in the water and you will then see rings start out from the 
point where the stone fell, these rings becoming larger and 
larger until they are finally lost ; but all the time these rings 
or very small waves have been going farther and farther from 
the centre. Now imagine the same thing occurring in the 
air. If you strike a bell, for instance, you know that the bell 
is vibrating, because if you put your finger on it you can 
feel this motion. This motion is given to the air, and the air 
vibrates in the same way, except that the vibrations travel 
through the air to our ear. 

459. Solids conduct sound even better than air does ; if you 
place your ear at one end of the table and strike the other end 
the sound which you hear will be very loud. 

460. How We Hear.— Now that we know what sound is, 
let us study how we hear. The waves of sound pass through 
the air and reach the outer' ear ; this is shaped so as to collect 
them and lead them into the canal to the drum-membrane. 
The waves of sound beat against this membrane and cause it 
to vibrate ; when this membrane vibrates, the bones of the 
middle ear must also move to and fro, because they are at- 
tached to it. The bones of the middle ear carry the vibra- 
tions to the internal ear, where the nerve of hearing ends in 
a large number of fine hairs, and these carry the sound to the 
brain. 

461. Deaf-Mutes. — Persons who cannot hear when they 
are children, and therefore cannot imitate sounds from other 
people, are called deaf-mutes. These unfortunate people have 
voices just like others ; but they cannot hear the sounds, and 
therefore they cannot speak in the ordinary way. But they 
can make themselves understood in two ways : One way is by 
means of signs and letters which they make with their fingers; 
they learn to do this very rapidly. The second method, and 
the newest, is to teach the deaf-mutes to talk by having them 
imitate the motion of our lips. It is surprising how well they 
learn to do this ; some of them are able to carry on a conversa- 



THE SENSES. 215 

tion and yet not hear what is spoken, but understanding it by 
watching the movement of the lips. 

462. Care of the Ears. — We should never try to pick out 
the wax in the ears with hairpins and other sharp instruments. 
A little wax is quite natural, and if too much is there it is best 
to let the doctor remove it, for we may injure the delicate 
parts of the ear. 

463. If water gets into the ear during bathing, hold the head 
over to one side and pull the outer ear up and down gently, 
and it will flow out. 

464. If an insect should crawl into the ear, a little soap and 
water will kill it, and at the same time bring it out. 

465. A blow upon the side of the head or over the ear is 
dangerous, because it sometimes affects the brain ; it may also 
tear the delicate drum-membrane and thus interfere with good 
hearing. 

466. The ears do not need to be washed out when they are 
healthy ; simply wash the outer ear and do not meddle with 
any of the deeper parts. 



SYNOPSIS. 

The Ear : 
Parts : 

1. Outer ear — Collects sound. 

2. Canal leading from outer to middle ear. 

3. Middle ear : 

a. Drum-membrane. 

b. Bones: (1) Hammer, (2) anvil, (3) stirrup. 

4. Internal ear — Nerve of hearing ends here in fine hairs, 
and conveys sound to brain. 

5. Eustachian tube — Leading from throat to middle ear. 
How we Hear : 

1. Vibration of sounding body. » 

2. Vibration of air. 

3. Strikes against drum-membrane. 



216 ANATOMY, PHYSIOLOGY, AND HYGIENE. 

4. Vibrations conducted by chain of bones to 

5. Internal ear, where they strike the hair-like ends of 

6. The nerve of hearing, which conducts sound to 

7. Brain. 



QUESTIONS. 

1. Into what three parts can the ear be divided ? 2. Why is the 
external ear shaped as it is ? 3. Can the lower animals move their 
ears ? 4. Of what use is this to them ? 5. What leads from the 
outer ear down to the middle ear ? 6. What is ear-wax ? 7. What 
are its uses ? 8. What is another name for the middle ear ? 9. 
Where is the drum-membrane ? 10. What is in the middle ear ? 
11. How are the bones of the middle ear arranged ? 12. What are 
the names given to the bones of the middle ear ? 13. What con- 
nects the throat with the middle ear? 14. Where is the internal 
ear ? 15. What is its form ? 16. What is in the internal ear ? 17. 
Where is the nerve of hearing ? 18. What does it do ? 19. How is 
sound produced ? 20. What conducts the sound ? 21. Can solids 
conduct sound ? 22. How can you prove this ? 23. Explain how 
we hear ? 24. What is meant by a deaf-mute ? 25. Has a deaf- 
mute any voice ? 26. Why cannot he talk without special teaching ? 
27. How do deaf-mutes make themselves understood? 28. Why 
should we not try to pick out the wax in our ears ? 29. How would 
you get rid of any insect that crawled into the ear ? 30. Why is a 
blow upon the side of the head or over the ear dangerous ? 



GLOSSAEY. 



Ab-do'men (Latin, abdere, to hide). The large cavity of the lower part 
of the trunk, below the diaphragm, in which the liver and the 
stomach, intestines, and other digestive organs are placed ; the 
belly. 

Ab-sorp'tion (Latin, ab, and sorbere, to suck up). The process of suck- 
ing up fluids by means of the blood-vessels or lymphatics. 

Ad'am's Ap'ple. The prominent angle of the larynx which can be 
seen and felt in the front of the neck. It is said to have been thus 
named from an old belief that the apple stuck in Adam's throat, 
thus causing this projection. 

Al'co-hol (Arabic, al kohl, a powder to paint the eyebrows with). A 
colorless fluid, resembling water in appearance, which forms the in- 
toxicating portion of beer, wine, and spirits. 

Ali-ment'a-ry Ca-nal (Latin, alere, to feed). The series of hollow 
organs in which the food is digested, or prepared for absorption by 
the blood. It comprises the mouth, pharynx, oesophagus, stomach, 
and intestines. 

A-nat'o-my (Greek, ana, up, and temnein, to cut). The study of the 
form and structure of the different parts of the body. 

A-or'ta (Greek, aeirein, to lift up). The large artery which arises 
from the left ventricle of the heart and passes down along the back- 
bone, giving off branches in its course. 

Ap'o-plexy (Greek, apo, away, and plessein, to strike). A sudden loss 
of consciousness, due to the bursting of a blood-vessel in the brain. 

A'que-ous (Latin, aqua, water). Watery. 

A'que-ous Hu'moPv (Latin, humere, to be moist). The few drops of 
watery fluid which fill the space between the cornea and the lens of 
the eyeball. 

Ar'ter-y (Greek, aer, air, and terein, to contain). A blood-vessel which 
conducts blood from the heart to the various tissues. The ancients 
believed that the arteries were filled with air ; hence the name. 



218 GLOSSARY. 

Au'ri-cle (Latin, auris, the ear ; auricula, a small ear). The upper 
cavity of the heart on each side ; so named from its fancied resem- 
blance to a dog's ear. 

Bi'-ceps (Latin, bis, twice, and caput, head). A large and strong mus- 
cle on the front of the arm, serving to bend the forearm upon the 
arm ; so called because it is attached to the bone by two portions 
called heads. 

Bicuspid (Latin, bis, twice, and cuspis, point). The name given to 
the fourth and fifth teeth on each side, on account of their possess- 
ing two elevations upon the crown. 

Bile (Latin, bilis, anger, bile). The gall ; the peculiar, yellowish or 
greenish fluid, bitter to the taste, formed in the liver, and emptied 
into the commencement of the small intestine. 

Bow'-el (Latin, botellus, a small sausage). The intestine ; the long 
hollow tube into which the partly-digested food passes from the 
stomach. 

Bron'chtjs j (Greek, brogclios, windpipe). The first two divis- 

Bron'chi (plural) \ ions of the windpipe, one passing to each lung. 

Bron'chi-al. Relating to the bronchi ; bronchial tubes, the smaller 
branches of the bronchi in the substance of the lung. 

Bun'ion. An enlargement and soreness of the great toe at the joint 
connecting it with the body of the foot. 

Ca-nine' (Latin, canis, dog). The sharp, pointed tooth on each side 
of the incisors ; so-called because they are very prominent in the 
dog. 

Cap'il-la-ries (Latin, capillus, hair). The smallest blood-vessels, con- 
necting the arteries and veins ; so called on account of their mi- 
nute, " hair-like " size. 

Cap'su-lar (Latin, capsula, a small box). A name used to qualify cer- 
tain ligaments which surround joints " like a box." 

Car-bon'ic Acid Gas (Latin, carbo, coal). The gas which is present in 
the air breathed out by animals ; it represents waste in animals, 
but serves as food for plants. 

Car-niv'o-rous (Latin, carnis, flesh, and vorare, to devour). Subsisting 
largely or entirely on flesh. 

Car'pus (Greek, carpos, the wrist). The collection of small bones, 
eight in number, forming the wrist. 

Car'ti-lage (Latin, cartilago, gristle). A solid elastic substance found 
in joints, in the nose and elsewhere ; gristle. 



GLOSSARY. 219 

Cell (Latin, cella, a storeroom). A small body, often rounded, form- 
ing one of the simplest parts of which the body is built up ; cells 
and fibres make up the greater part of the body. 

Cer'e-bel'ltjm (Latin, diminutive of cerebrum, the brain). The little 
brain, placed beneath the back part of the rest of the brain. 

Cer'e-brum (Latin). The larger portion (seven-eighths) of the brain. 

Chest (Latin, cista, a box). The upper cavity of the trunk inclosed by 
the breast-bone, ribs, and spinal column, and containing the heart 
and lungs. 

Chlo'ral (Greek, cliloros, pale green). A drug used to produce sleep. 

Cho'rold (Greek, chorion, a membrane). The middle coat of the eye- 
. ball. 

Cir-cu-la'tion (Latin, circulus, a ring). The course of the blood through 
the heart and blood-vessels of the body ; from heart to arteries, 
through capillaries to veins, back to heart. 

Clav'i-cle (Latin, clavicula, a little key, from clams, key). The long, 
slender bone extending across the upper part of the front of the 
chest ; the collar-bone. 

Clot. The dark-red, semi-solid mass which results when blood is 
withdrawn from the blood-vessels. 

Co'ca-ine (Spanish, coca, a Peruvian plant). A drug used to make cer- 
tain parts insensitive to pain. 

Com-bus'tion (Latin, comburere, to burn). Aburning-up ; applied to the 
process taking place in the body by which the tissues are consumed, 
to be replaced by elements in the blood. 

Corn (Latin, cornu, a horn). A small elevation due to thickening of 
the outer layer of the skin ; corns usually appear upon the toes and 
are caused by pressure from shoes which do not fit properly or are 
too tight. 

Cor'ne-a (Latin, cornu, a horn). The transparent membrane which 
forms the front of the eyeball. 

Cor'o-nal (Latin, corona, crown). A name given to the suture which 
unites the frontal with the parietal bones, because the crown of a 
king rests in part upon this line. 

Cor'pus-cles, Blood (Latin, corpus, a body ; corpusculum, a small body). 
The small bodies, some red, some white, found floating in the fluid 
part of the blood. 

Cos-met'ic (Greek, kosmos, ornament). Preparations which when ap- 
plied to the skin are supposed to increase its beauty. 

Cra'ni-um (Latin). That portion of the skull which incloses the brain. 

Crown (Latin, corona, a crown). The top of the skull. 



220 GLOSSARY. 

Crystal-line (Latin, crysiallum, a crystal). Like glass ; applied to 
the lens in the interior of the eye on account of its transparent 
properties. 

Dan'druff. The small scales, corresponding to the outer layer of the 
skin, which fall off the scalp. 

Deaf-mute. A person who is deaf and dumb. 

De-lir'i-um (Latin, delirare, to wander in mind). A condition in which 
the ideas of a person are wild and wandering. 

De-lir'i-um Tre'mens (Latin, tremere, to tremble). The condition of 
being out of the mind which results from over-indulgence in alco- 
holic drink. 

Dentine (Latin, dens, a tooth). The hard material which forms the 
main part of the tooth between the pulp within and the enamel on 
the surface. 

Di'a-phragm (Greek, diaphrassein, to divide by a partition). The 
sheet of muscular tissue which separates the chest from the ab- 
domen. 

Di-gest' (Latin, digerere, to separate). To separate the food into nutri- 
tious juices which can be absorbed by the system and matters which 
are cast off. 

Dislo-ca'tion (Latin, dislocare, to put out of place). The separation, 
by accident, of the ends of bones forming a joint. 

Drum Mem'brane. The small sheet of tissue which separates the outer 
from the middle ear, and serves to transmit sounds to the interior 
of the ear. 

Duct (Latin, ducere, to lead). A narrow tube, such as the bile-duct. 

Duo-de'num (Latin, duodeni, twelve each). The first portion of the 
small intestine ; so called because its length is about twelve fingers' 
breadth. 

Dys-pep'si-a (Greek, dm, difficult, and peptein, to digest). A disordered 
state of the organs of digestion giving rise to difficult or painful di- 
gestion. 

En-am'el. The hard layer which covers the crown of the tooth. 

Epi-dem'ic (Greek, epidemos, among the people). A disease which at- 
tacks a large number of persons of one neighborhood at the same 
time. 

Epi-glot'tis (Greek, epi, above, and glotta, the tongue). A leaf-shaped 
piece of cartilage which covers the entrance to the larynx during 
swallowing. 



GLOSSARY. 221 

Eu-sta'chi-an Tube. The tube which leads from the throat to the 

middle ear ; so called from the physician who first described it. 
Ex-pi-ra'tion. The act of breathing out. 
Ex-pire' (Latin, ex, out, and spirare, to breathe). To breathe out. 

Faint' ing. Loss of consciousness, due usually to an interference with 

the circulation. 
Fang. The long, pointed end or root of a tooth. 
Fari-na'ceous (Latin, farina, flour). Containing starch ; starchy. 
Far-sighted. Having one of the forms of defective sight. 
Fe'mur (Latin). The thigh-bone. 
Fermen-ta'tion (Latin, fervere, to be boiling hot). The change by 

which starch or sugar in a liquid is converted into alcohol and a gas. 
Fi'bre (Latin, fib?*a, a thread). One of the tiny threads of which a 

large portion of the body is formed. 
Fib'u-la (Latin, fibula, a clasp). The outer, long, slender bone of the 

leg. 
Flesh'y. Applied to animal food, especially meat, in distinction from 

vegetable food. 
Fract'ure (Latin, frangere, to break). The breaking of a bone. 
Front'al (Latin, from, the forehead). Belonging to the forehead. 
Func'tion (Latin, functio, performing). The special work of any organ 

of the body. 

Gall. The bile. 

Gas'tric (Greek, gaster, the stomach). Belonging to the stomach. 

Gas'tric Juice. The fluid secreted by the stomach, which digests 
fleshy food. 

Gel'a-tin (Latin, gelare, to congeal). An animal substance found in 
bones, cartilage, and other tissues, which dissolves in boiling-water, 
and forms a firm jelly upon cooling. 

Gland (Latin, glans, an acorn). An organ which separates certain 
substances from the blood. 

Gout (Latin, gutta, drop). A disorder of the system in which one of 
the prominent symptoms is a painful affection of the joints. 

Gran'u-lar Lids (Latin, granum, grain). A contagious affection of 
the eyelids, so-called, because the lids, when turned out, often pre- 
sent the appearance of being studded with small grain-like bodies. 

Gris'tle. Cartilage. 

Groin. The depression on each side, between the abdomen and thigh, 
just below the hip. 



222 GLOSSARY. 

Gul'let (Latin, gula, throat). The tube between the throat and stom- 
ach, serving for the passage of food and drink ; the oesophagus. 

Hang'nail. A small flake of skin which hangs from the side or root 

of a nail. 
Hem'i-spheres (Greek, hemi, half, and sphaira, a sphere). The halves 

into which the cerebrum is divided. 
Hem'or-rhage (Greek, haima, blood, and regnumi, to burst). The es- 
cape of blood from the blood-vessels ; any bleeding. 
Her-biv'o-rotjs (Latin, herba, herb, and vorare, to devour). Subsisting 

on vegetable food. 
Hip. The projection on each side of the body just above the thigh 

formed by the hip-bone. 
Hops. A plant, the flowers of which are used in flavoring beer. 
Hu'man (Latin, homo, man). Relating to man. 
Humerus (Latin). The thigh-bone. 
Hu'mor (Latin, humere, to be moist). An animal fluid ; especially the 

fluid contents of the eyeball. 
Hy'gi-ene (Greek, Hygeia, the goddess of health). The science which 

treats of the preservation of health and the prevention of disease. 



In-ci'sor (Latin, incidere, to cut in). The four front teeth in both jaws ; 
they have sharp, chisel-like edges. 

In'dex Fin'ger (Latin, indicare, to point out). The fore-finger ; the 
finger next to the thumb. 

In-di-gest'i-ble (Latin, in, not, and digerere, to separate). Not easily 
converted by the organs of digestion so as to be fit for absorption 
by the blood and tissues. 

In-di-ges'tion (Latin, in, not, and digerere, to separate). A condition 
in which the food is not properly digested, or digested with diffi- 
culty. 

In-spire' (Latin, in, in, and spirare, to breathe). To draw in breath. 

In-spi-ra'tton (Latin, in, in, and spirai'e, to breathe). The act of in- 
spiring or drawing in breath. 

In'step. The raised portion of the foot near the ankle. 

In'tel-lect (Latin, intelligere, to understand). The power which en- 
ables us to judge and understand. 

In-tes'tine (Latin, intus, on the inside). The hollow tube which fills 
the greater part of the abdomen, and forms the continuation of the 
digestive organs after the stomach ; the bowels. 



GLOSSAKY. 223 

In-tox'i-cating (Latin, toxicum, an arrow-poison). Making drunk ■ 

capable of bringing under the effects of alcohol. 
In-vol'un-ta-ry (Latin, in, not, and voluntas, will). Not dependent 

upon the will. 
I'ris (Latin, iris, the rainbow). The colored membrane in the front 

portion of the eye, perforated in its centre by the pupil. 

Jaun'dice (Latin, galbus, yellow). The yellowish discoloration of the 

skin and of the white of the eye, due to bile being present in the 

blood. 
Joint (Latin, jungere, to bind together). The place of meeting or union 

of two or more bones. 
Judg'ment (Latin, judicare, from jus, law, and dicare, to proclaim). 

The faculty of judging or deciding correctly. 

Kid'ney. An important organ placed in the back part of the abdom- 
inal cavity ; it separates certain refuse materials from the blood ; 
there are two kidneys. 

Lach'ry-mal (Latin, lacrima, a tear). Forming tears. 

Lach'ry-mal Duct. The small canal which conveys the tears from 
the eye to the interior of the nose. 

Lach'ry-mal Gland. The small organ, placed just above the eye, 
which produces the tears. 

Lac'te-als (Latin, lac, milk). The small vessels (part of the lymph- 
atics) which carry the nutritious juices representing the digested 
food, from the intestines to the blood, emptying into a large vein 
of the neck. 

Lam'b-dold (Greek letter lambda, A). The name given to the suture 
which connects the occipital with the parietal bones, on account of 
its resemblance in shape to the Greek letter lambda (A). 

Lar'ynx (Greek, larugx, a whistle). The upper part of the air-passage 
in w T hich the voice is produced. 

Lean (Latin, lenis, soft, moderate). Thin ; devoid of fat. 

Lens (Latin, lens, a lentil). A transparent body with curved surfaces, 
which influence the course of rays of light. The lens of the eye is 
the transparent body placed just behind the iris and pupil, which 
causes images to fall upon the retina or nervous layer of the eye- 
ball. 

Lig'a-ment (Latin, ligare, to bind). The tough bands or sheets of tis- 
sue which cover the joints and bind the ends of the bones together. 



224 GLOSSARY. 

Limbs. The extremities of the human body attached to the trunk on 
each side, above and below ; there are two upper and two lower 
limbs. 

Liq'uor (Latin, liquere, to be liquid). A name given to strong alco- 
holic fluids, such as whiskey, brandy, rum, etc. 

Little Finger. The smallest finger ; situated on the opposite side of 
the hand from the thumb. 

Lungs. The organ of breathing, occupying the greater part of the 
cavity of the chest. 

Lymph (Latin, lympha, pure water). The colorless or white fluid con- 
tained in the lymphatics. 

Lym-phat'ics (Latin, lympha, pure water). The small vessels which 
run from the tissues and finally empty into two large veins in the 
neck ; they contain lymph. 

Mag'nt-fied (Latin, magnus, great, and facere, to make). Made to ap- 
pear larger than in reality. 

Ma'lar (Latin, mala, the cheek). The bone which forms the promi- 
nence of the cheek. 

Malt. Sprouting barley which has been dried by heat so as to change 
its starch into sugar ; it is used in brewing beer. 

Mar'row. A soft, fatty substance contained in the central cavity of 
bones. 

Me-dul'la (Latin, medulla, marrow, pith). The portion of the brain 
which connects it with the spinal cord. 

Meta-car'pus (Greek, mela, beyond, and karpos, the wrist). That 
part of the skeleton of the hand between the wrist and the fin- 
gers. 

Meta-tar'sus (Greek, meta, beyond, and tarsos, ankle). That part of 
the skeleton of the foot between the heel and the toes. 

Mi'cro-scope (Greek, mikros, small, and skopein, to view). An optical 
instrument, consisting of a combination of lenses, used to view ob- 
jects which are too small to be seen by the naked eye. 

Mid'dle Finger. The finger placed midway between the thumb and 
little finger ; the third finger. 

Min'er-al (Latin, mina, a mine). Derived from the inorganic or life- 
less world ; such as the rocks. 

Mo' lars (Latin, molere, to grind in a mill). The three rear teeth in each 
jaw ; they are used in grinding the food into small particles. 

Mor'phine (Greek, Morpheus, the god of sleep). A white substance 
which constitutes the narcotic principle in opium. 



GLOSSAKY. 225 

Mucus (Latin, mucus, slime). A slippery substance secreted by the 

mucous membranes to keep them moist. 
Mu'cous Mem'brane (Latin, mucosus, from mucus, slime, and mem- 

brana, a skin). The soft layer of tissue which lines the alimentary 

and breathing channels ; it secretes mucus. 
Mus'cles (Latin, musculus, a muscle). The fleshy organs which move 

the various parts of the body. 

Nar-cot'ic (Greek, narke, numbness). A drug which relieves pain 
and produces sleep ; when given in large quantity, produces insen- 
sibility and even death. 

Na'sal (Latin, nasus, the nose). Pertaining to the nose. 

Near'-sighted. A form of weak sight in which objects can only be 
seen clearly when held very close. 

Nerves (Latin, nervus, a nerve). The thread-like bundles of fibres 
which run from the brain and spinal cord to different parts of the 
body and establish communication. 

Ni'trogen (Latin, nitrum, nitre, and genere, to produce). The gas 
which forms four-fifths of the atmosphere ; it serves to dilute the 
oxygen. 

Nostril. One of the two oval apertures at the front of the nose 
through which air is drawn. 

Oc'ci-put (Latin, oc, back, and caput, the head). The hind part of the 

head or of the skull. 
Oc-cip'i-tal, (Latin, oc, back, and caput, the head). Referring to the 

back part of the head. 
Oc'u-list (Latin, oculus, the eye). One who treats diseases of the eye. 
(E-soph'a-gus (Greek, oiso (future of), to carry, and phagein, to eat). 

The passage for food, leading from the throat to the stomach. 
O'pi-um. A narcotic drug obtained from the fruit of the poppy plant. 
Op'tic (Greek, opticos). Pertaining to sight. Optic nerve, the nerve of 

sight. 
Orb'its (Latin, orbis, a circle). The cavities in which the eyes are 

placed. 
Or'gan (Latin, organum, an organ). A part of the body which per- 
forms some special work ; the eye is the organ of sight. 
Ox'y-gen (Greek, oxus, acid, and genein, to produce). An important 

gas which forms one-fifth of the atmosphere, and serves to sustain 

life. 

15 



226 GLOSSARY. 

Pan'cre-as (Greek, pan, all, and kreas, flesh). An important organ of 
digestion, situated in the abdominal cavity and pouring its secre- 
tion, the pancreatic fluid, into the small intestine. 

Pa-ral'y-sis (Greek, para, beside, and luein, to loosen). Loss of the 
power of moving a greater or lesser number of muscles. 

Par'a-lyzed (Greek, para, beside, and luein, to loosen). Affected 
with loss of the power of moving a greater or lesser number of the 
muscles. 

Pa-ri'e-tal (Latin, paries, a wall). A name given to the two bones 
which form the roof of the skull. 

Pa-rot id (Greek, para, beside, and ous, the ear). A gland situated be- 
low and in front of the ear ; it secretes part of the saliva. 

Pa-tel'la (Latin, patina, a pan). The knee-pan. 

Pec'to-ralis (Latin, pectus, the breast). The triangular muscle on 
each side of the front of the chest which draws the arm inward. 

Pel/vis (Latin, pelvis, a basin). The bony basin at the lower part of the 
chest to which the thigh-bones are attached. 

Pep' sin (Greek, pepsis, digestion). A substance present in the gastric 
juice, which digests fleshy food. 

Peri-car'di-um (Greek, peri, around, and kardia, the heart). The sac 
which surrounds the heart. 

Peri-os'te-um (Greek, peri, around, and osteon, a bone). A tough 
membrane closely covering the bones. 

Peri-to-ne'tjm (Greek, peri, around, and teinein, to stretch). The 
smooth membrane which covers the abdominal organs and lines 
the cavity of the abdomen. 

Per-spi-ra'tion (Latin, per, through, and spirare, to breathe). The 
watery fluid given off from the skin ; when visible it is called 
" sensible ; " when invisible " insensible." The sweat. 

Pha-lan'ges — Plural of phalanx (Greek, phalanx, a rank). The small 
bones forming the fingers and toes. 

Pharynx (Greek, pharugx, the throat). The cavity at the back of the 
mouth through which the food passes on its way to the oesophagus 
or gullet. 

Physi-ol'o-gy (Greek, pJiusis, nature, and logos, a discourse). The 
study of how beings live. 

Plas'ma (Greek, plassein, to mold). The liquid part of the blood. 

Pleu'ra (Greek, pleura, the side). The smooth membrane which cov- 
ers the lungs and lines the cavity of the chest. 

Pores (Latin, porus, a passage). The minute openings in the skin 
through which the perspiration escapes. 



GLOSSARY. 227 

Pulmo-na-ry (Latin, pulmo, a lung). Pertaining to the lungs. 

Pulp (Latin, pulpa, pulp). The soft material which fills the central 

space in the teeth. 
Pulse (Latin, pulsus, the pulse). The beating of the arteries. 
Pupil (Latin, pupilla, pupil). The opening in the iris through which 

light passes into the interior of the eye. 
Py-lo'rus (Greek, puloros, a gate-keeper). The opening in the stomach 

by which food passes into the intestines. 



Ra'di-us (Latin, radius, a rod). The outer bone of the forearm. 

Rea'son (Latin, ratio, reason). The power by which we distinguish 
right from wrong, and are able to employ proper means for the at- 
tainment of particular ends. 

Re'flex Action (Latin, re, back, and flectere, to turn). Actions excited 
without our being conscious of them. 

Re-spire' (Latin, re, again, and spirare, to breathe). To breathe. 

Respi-ra'tion (Latin, re, again, and spirare, to breathe). The act of 
breathing. 

Ret'i-na (Latin, rete, a net). The innermost or nervous layer of the 
eyeball which receives the impressions of sight. 

Rib. One of the long, slender bones inclosing the chest. 

Ring Finger. The finger next to the little finger, upon which rings 
are usually worn. 

Sag'it-tal (Latin, sagitta, an arrow). Pertaining to an arrow ; a name 
given to the suture which unites the parietal bones, because it meets 
the coronal suture as an arrow meets the bow. 

Sa-li'va (Latin, saliva, spittle). The liquid secreted by the glands near 
the mouth, emptied into this cavity and serving to keep the mouth 
moist and to form a mass with the food ; the spittle. 

Sal'i-va-ry. Pertaining to saliva or spittle. 

Scalp (Latin, scalpere, to carve). The skin covering the top of the 
head. 

Scap'u-la (Latin). The shoulder-blade. 

Scarp'-skin. The outer layer of the skin. 

Scent (Latin, seniire, to smell). Odor ; smell. 

Scler-ot'ic (Greek, skleros, hard). The firm, white, outer layer of the 
eyeball. 

Sen-sa'tion (Latin, sentire, to feel). Feeling caused by external ob- 
jects. Nerves of sensation are those which carry impressions of 



228 GLOSSARY. 

touch, pain, heat, etc., from the various organs of the body to the 

brain. 
Senses (Latin, sentire, to feel). The faculty of obtaining information 

of the exterior world by means of certain organs ; the five senses 

are, feeling, seeing, hearing, smelling, and tasting. 
Sen'si-tive (Latin, sentire, to feel). Having a high degree of feeling. 
Skel'e-ton (Greek, skellein, to dry up). The system of bones which 

constitutes the framework. 
Skull. The bones of the head taken collectively. 
Sole (Latin, soled). The under surface of the foot. 
Sol'u-ble (Latin, solvere, to dissolve). Capable of being dissolved in a 

fluid. 
Spe'cial Senses (Latin, specialis, a particular kind). The sense of 

taste, smell, sight, and hearing as distinguished from the general one 

of feeling. 
Spi'nal (Latin, spina, the spine). Relating to the spine or backbone. 

Spinal canal, the canal running through the back part of the back- 
bone or spine, in which is contained the soft bar of nervous tissue 

called the spinal cord. 
Spleen (Latin, splen). A large, flat body, composed largely of blood, 

placed on the left side of the abdominal cavity. 
Squint. The condition of being cross-eyed. 
Starch. The white grains found in wheat, potatoes, and many other 

plants. 
Stek'num (Greek, stemon, the breast). The breast-bone. 
Stim'u-lant (Latin, stimulare, to incite). Anything which produces an 

increase of action in the system or any part of it. 
Stom'ach (Greek, stoma, an entrance). The receptacle for the food, 

placed between the lower end of the gullet and the beginning of the 

intestines. 
Sub-lin'gual (Latin, sub, under, and lingua, the tongue.) Situated 

under the tongue. Sublingual glands, two salivary glands placed 

underneath the tongue. 
SuB-MAx'iL-LA-RY (Latin, sub, under, and mala, jaw). Situated beneath 

the jaw. Submaxillary glands, two salivary glands placed under- 
neath the lower jaw. 
Sut'ure (Latin, suere, to sew). The line of union between the bones 

of the skull. 
Syn-o'vi-al (Latin, ovum, an egg). Relating to the fluid found in 

joints. Synovial fluid, the fluid secreted in joints to permit of easy 

motion. It is formed by a sac known as the synovial membrane. 



GLOSSARY. 229 

Sys'tem (Latin, systema). A collection of parts of the body performing 
the same function ; for instance, all the arteries of the body taken 
collectively are known as "the arterial system." Tne term system 
is also used to denote the body as a whole. 

Tarsus (Greek, tarsos, the ankle). The solid, hind part of the foot 
which is joined to the leg. 

Tem'ple (Latin, tempus, time). A spot on the side of the head, just in 
front of the ear, so-called because the hair begins to turn gray in 
this situation, at the approach of age. 

Tem'po-ral (Latin, tempus, time). Pertaining to the temple. 

Ten'don (Latin, iendere, to stretch). The strong, fibrous part of a 
muscle by which it is attached to surrounding parts, especially bone. 

Thermometer (Greek, thermos, hot, and metron, measure). An in- 
strument used to measure the intensity of heat. 

Thigh. The thick, fleshy portion of the lower extremity, between the 
lower end of the trunk and the knee. 

Tho'rax (Greek, thorax, a breast-plate). The chest. 

Thumb. The short, thick finger ; the first from the outer side. 

Tib'i-a (Latin). The inner bone of the leg. 

Tis'stje (Latin, texere, to weave). A form of material of the body, 
composed of various elementary substances, such as cells, fibres, 
nerves, blood-vessels, etc., closely connected with each other. 

To-bac'co (Indian, tabaco, the tube or pipe in which the Indians smoked 
tobacco). A plant much used for smoking, chewing, and snuffing. 

Tra'che-a (Greek, trachus, rough). The windpipe ; the canal which 
conveys air to the lungs. 

Train (Latin, trahere, to draw). To prepare the body for extraordi- 
nary feats of strength or endurance. 

Tri'ceps (Latin, tria, three, and caput, head). The large muscle on the 
back of the arm ; so-called, because it is formed above of three 
portions. 

Trunk (Latin, truncus, trunk). The central part of the body, to which 
head and limbs are attached. 

Tu'bule (Latin, tubus, a pipe). A small tube. 

Ul'na (Latin, ulna, elbow). The inner bone of the forearm. 

Valve (Latin, valva, a folding-door). A lid or cover so formed as to 

open in one direction and close in the other. 
Ve'ge-ta-ble (Latin, vegetare, to enliven). Relating to plants. 



230 GLOSSARY. 

Vein (Latin, vena, vein). One of the blood-vessels which receives 

blood from the capillaries and returns it to the heart. 
Ventilation (Latin, ventnlus, a slight wind). The act of removal of 

impure air and admission of pure air. 
Ven'tri-cles (Latin, ventriculus, dim. of venter, the belly). The two 

lower and larger cavities of the heart. 
Vertebra (Latin, vertere, to turn). One of the bones which make up 

the spine or backbone. 
Vit're-ous (Latin, vltrum, glass). Like glass. Vitreous humor, the 

transparent, jelly-like substance which fills the eyeball, behind the 

lens. 
Vo'cal (Latin, vox, voice). Relating to the voice-sounds ; vocal cords, 

the bands of membrane existing in the larynx, which produce the 

voice-sounds by their vibration. 
Vol/un-ta-ry (Latin, voluntas, will). Produced by an act of the will. 

Windpipe. The passage by which air reaches the lungs. The 
trachea. 

Yeast. A substance added to starchy or sugary liquids to produce 
fermentation. 



INDEX. 



Abdomen, 17, 18, 217 
Absinthe, 72 
Absorption, 96, 217 
Achilles, tendon of, 56 
Adam's apple, 131, 217 
Air, 107 
changes produced in, by breath- 
ing, 139 
purification of, 140 
Air-passages, 134, 135 
Air-spaces, 137 
Air-vesicles, 137 
Alcohol, 71, 217 
and digestion, 98 
effects of, on arteries, 122 
on the circulation, 121 
on the heart, 121 
on the liver, 95 
on the muscles, 57 
on the nervous system, 175 
on the skeleton, 26 
on the stomach, 89 
on the system, 73 
manufacture of, 71 
moral effects of, 74 
properties of, 71 
Alcoholic drinks, 71 
effects of, on system, 73 
manufacture of, 72 
varieties of, 72 
Alcoholic habit, 73 



Ales, 72 

Alimentary canal, 79, 80, 217 
Anatomy, 13, 217 

Animals and plants, differences 
between, 15 

similarity in structure of, 159 
Animals, carnivorous, 64 

difference in food of, 64 

herbivorous, 64 

warm-blooded and cold-blooded, 
151 
Anvil, 212 
Aorta, 116, 117, 217 
Apoplexy, 122, 217 
Apple, Adam's, 131, 217 
Aqueous humor of eye, 203, 217 
Arch of foot, 17, 18, 36 
Arm, bone of, 20, 22, 34 
Arm-pit, 17, 18 
Arteries, 104, 117, 217 

effects of alcohol on, 122 
Artery, pulmonary, 114 
Auricles of heart, 113, 218 



Backbone, 31 

Ball-and-socket joint, 
Bathing, 190 

after meals, 97 
Baths, cold, 190 

Russian, 191 

Turkish, 191 



44 



232 



INDEX. 



Baths, warm, 190 
Beats of heart, 113 
Beef, 67 
Beers, 72 
Beings, living, 14 
Biceps, 53, 54, 55, 218 
Bicuspid teeth, 82, 218 
Bile, 94, 218 

action of, 94 
Birds, blood of, 107 
Bleeding, 120 

treatment of, 120, 121 
Blindness, 205 
Blood and circulation, 105 

questions on, 127 

synopsis of, 124 
Blood and tissues, changes in, pro- 
duced by breathing, 139 
Blood, appearance of, 105 

clotting of, 109 

color of, 105 

composition of, 105 

course of, 113, 115 

difference between, in arteries 
and in veins, 108 

importance of, 105 

purification of, 115 

serum of, 109 
Blood-clots, value of, 109 
Blood-corpuscles, 105, 219 
Blood-globules, 105 

red, 106 
use of, 107 

white, 106 
Blood-heat, 151 
Blood of other animals, 107 
Blood-plasma, 107 
Blood-vessels, 104, 117 
Body, parts of, 15, 17 

subdivisions of, 15 
Body-heat, 148, 151 



Body-heat, in sickness, 152 

regulation of, 152 
Bone, composition of, 24 

structure of, 24 
Bones, forms of, 23 

number of, 23 

uses of, 21 

of the cranium, 27 

of the ear, 212 

of the face, 27, 28 

of the lower limbs, 35 

of the skull, 27 

of the trunk, 30 

of the upper limbs, 34 
Bowels, 80, 90, 218 
Brain, 161, 163, 164, 165, 169 

coverings of, 163 

divisions of, 165 

functions of, 168 

size of, 163 

training of, 16$ 

weight of, 163 
Brandy, 73 
Bread, 67 

Breast-bone, 20, 22, 32, 34 
Breathing and smelling channels, 

196 
Breathing, changes which it pro- 
duces on blood and tissues, 
139 

changes which it produces in the 
air, 139 

effect of tight clothing upon, 143 

frequency of, 138 

involuntary nature of, 138 

movements of chest in, 138 

mouth, 138 

organs of, 130 
synopsis of, 144 
questions on, 146 
Bridge of nose, 196 



INDEX. 



233 



Bronchial tubes, 218 
Bronchi, 131, 135, 218 
Bronchus, left, 135, 218 

right, 135, 218 
Brows, 202 
Bunion, 25, 218 

Burning of fuel, results of, 149 
Butter, 68 

Calf op leg, 17 

Canal, alimentary, 79, 80, 217 

of ear, 211 

from liver and gall-bladder, 92 

from pancreas, 63 

spinal, 31, 228 
Canine teeth, 82, 218 
Capillaries, 117, 118, 218 
Capsular ligaments, 43, 44, 218 
Carbonic acid gas, 108, 139, 218 
Care of circulation, 121 

of ears, 215 

of eyes, 207 

of hair, 192 

of muscles, 56 

of nails, 192 

of skin, 189 

of teeth, 83 
Carnivorous animals, 64, 218 
Carpus, 20, 22, 35, 218 
Cartilage, 25, 218 
Casting off refuse materials, 150 
Cavities of heart, 112 
Cells, 16, 218 

of liver, 94 

of stomach, 88 
Cerebellum, 105, 167, 219 
Cerebrum, 165, 166, 219 

gray and white portions of, 166 

hemispheres of, 166, 222 
Cheese, 68 
Chest, 18, 20, 22, 33, 219 



Chest, deformed, 25, 143 

movements of, in breathing, 138 

muscle of, 55 
Chewing-gum, effects of, 84, 97 
Chloral, 173, 219 

habit, 173 
Chocolate, 66 

Choroid coat of eye, 202, 219 
Circular piece of larynx, 132 
Circulation, 110, 115, 219 

and exercise, 121 

care of, 121 

course of, 113, 115 

discovery of, 114 

effects of alcohol on, 121 

effects of tobacco on, 122 

rapidity of, 119 

through lungs, 114, 115 
Clavicle, 20, 22, 32, 34, 219 
Clot, 109, 219 
Clothing, 152, 191 

woollen, 152 
Clotting of blood, 109 
Coats of eye, 202 

of intestines, 90 
Cocaine, 175, 219 

habit, 175 
Coccyx, 31 
Coffee, 66 

effects of, on nervous system, 177 
Cold-blooded animals, 151 
Cold, effects of, 154 

in head, 197 
Collar-bone, 20, 22, 32, 34 
Color of hair, 189 

of skin, 186 
Column, spinal, 30, 31 
Combination of all forms of food, 

necessity for, in man, 66 
Combustion, 148, 219 
Contraction of muscles, 51 



234 



INDEX. 



Cooking, methods of, 69 
Cool, keeping, in summer, 153 
Cord, spinal, 31, 162, 169, 170, 228 

functions of, 171 

injuries to, 170 

structure of, 170 
Cords, vocal, 132, 133, 230 
Cornea, 202, 219 
Corns, 25, 219 
Coronal suture, 42, 219 
Corpuscles, blood, 105, 219 
Cosmetics, 192, 219 
Course of blood, 113, 115 

of inspired air, 130 
Cranial nerves, 167 
Cranium, bones of, 27, 219 

method of union, 28, 29 
Cream, 68 
Cross-eye, 204 
Crown of head, 16, 219 
of tooth, 81 

Dandruff, 186, 220 
Deaf-mutes, 214, 225 
Deformed chest, 143 

foot, 26 
Delirium tremens, 176, 220 
Dentine, 81, 220 
Diaphragm, 34, 220 
Digestion, 79, 220 

and excitement, 97 

effects of alcohol upon, 98 

effects of tobacco on, 98 

habits which are injurious to, 
97 

of fatty food, 96 

of fleshy food, 96 

of starchy food, 96 

organs of, 79, 80 

questions on, 102 

synopsis of, 98 



Discovery of action of the stomach, 
89 

of circulation, 114 
Dislocations, 44, 220 
Dress, effect of, on skeleton, 25 
Drinking-water, 69 

from wells, 69 

impure or poisoned, 69 

poisoning by lead, 71 

purification of, 71 

purity of, 69 
Drink, alcoholic, 72 

effects of, 73 
Drum of ear, 211 
Drum-membrane of ear, 212, 220 
Duct, nasal, 207, 220 

tear-, 207, 220 
Duodenum, 80, 90, 220 
Dyspepsia, 97, 220 

Ear, bones of, 212 

canal of, 211 

care of, 215 

communication with throat, 212 

drum of, 211 

drum-membrane of, 212 

internal, 213 

middle, 211 

outer, 211 

parts of, 211 

questions on, 216 

synopsis of, 215 
Ear-wax, 211, 215 
Easily digested food, 89 
Eating excessively, 97 

quickly, 97 
Eggs, 68 

Enamel of tooth, 81, 220 
Epidemics, 70, 220 
Epiglottis, 132, 220 
Eustachian tube, 213, 220 



INDEX. 



235 



Excessive eating, 97 
Excitement and digestion, 97 
Eye, 201, 202 

care of, 207 

choroid coat of, 202 

coats of, 202 

fluids of, 203 

good light for, 207 

humors of, 203 

interior of, 203 

lens of, 203 

muscles of, 204 

nerve of, 205 

nerve-coat of, 203 

parts of, 202 

protections to, 201 

pupil of, 203 

questions on, 210 

resemblance of, to photogra- 
pher's camera, 205 

rest for, 207 

sclerotic coat of, 202 

synopsis of, 209 
Eyebrows, 202 
Eyelashes, 202 
Eyelids, 202 
Eye-tooth, 82 
Exercise, 191 

and muscles, 56 

and the circulation, 121 

amount of, 57 

forms of, 57 

immediately after meals, 97 

necessity for, 57 
Expression of the face, effect of 

muscles on, 53 
Expiration, 130, 221 

Face, 16 
bones of, 27, 28 
expressions of, 53 



Fainting, 120, 221 

treatment of, 120 
Fang of tooth, 81, 221 
Farinaceous food, 64, 221 
Far-sightedness, 208, 221 
Fat, 48, 66 

digestion of, 96 

uses of, 49 
Fatty food, 66 
Feet, deformed, 25, 26 
Femur, 20, 22, 35, 36, 221 
Fermentation, 72, 221 
Fibres, 16, 221 
Fibula, 20, 22, 36, 221 
Filth, results of, 189 
Fingers, 35 

names of, 18 
Fish, 67 

Fishes, blood of, 107 
Flesh, 47 
Fleshy food, 64, 221 

digestion of, 96 
by stomach, 88 
by intestines, 92 
Fluid, synovial, 43 
Fluids of the eye, 203 
Fly-trap, Venus', 14 
Food and drink, 63 

essential to life, 63 

questions on, 77 

synopsis of, 75 
Food and oxygen produce heat and 

work, 150 
Food of plants, 64 

and animals, difference in, 64 
Food, different kinds of, required 
by man, 64 

easily digested, 89 

farinaceous, 64 

fatty, 66 
digestion of, 96 



236 



INDEX. 



Food, fatty, digestion of, in small 
intestine, 92 
fleshy, 64 
digestion of, 88, 96 
digestion of, in small intestine, 
92 
heavy, 89 
indigestible, 89 
light, 89 

passage for, 134, 135 
proper, 68 

results of combustion of, 149 
some of simplest forms of, 67 
starchy, 64 
digestion of, 96 
digestion of, in small intestine, 
92 
sugary, 66 
variety in, 68 
vegetable, 64 
Foot, arch of, 17, 18 
bones of, 20, 22, 36 
instep of, 17, 18 
sole of, 17, 18 
Forearm, bones of, 20, 22, 34 
Fracture of bones, 25, 26, 221 
Frontal bone, 27, 29, 221 
Fuel, results of burning of, 149 
Function, 15, 221 

Gall, 93, 94, 221 
Gall-bladder, 93, 94 

canal from, 92 
Gas, carbonic acid, 108, 139 
Gastric juice, 87, 221 

function of, 88 
Gastric tubules, 87, 88 
Gelatin, 24, 221 
Gin, 73 
Glands, 83, 221 

lachrymal, 206 



Glands, parotid, 84 

salivary, 83 

sublingual, 84 

submaxillary, 84 

tear, 206 
Gliding-joints, 43 
Globules, blood, 105 
Gout, 95, 221 
Granular lids, 208, 221 
Green vegetables, 66 
Gristle, 25, 221 
Groin, 17, 18, 221 
Gullet, 84, 85, 134, 221 
Gum-chewing, 97 

effects of, 84 

Habit, alcohol, 73 

cocaine, 175 

morphine, 174 

opium, 174 
Habits which are injurious to di- 
gestion, 97 
Hair, 188 

care of, 192 

color of, 189 

parts of, 188 

root of, 188 
Hammer, 212 
Hangnails, 192, 222 
Harvey, 114 
Head, 16 

bones of, 27 

cold in, 197 
Hearing, manner of, 214 

nerve of, 213 

questions on, 216 

sense of, 211 

synopsis of, 215 
Heart, 111, 112 

auricles of, 113 

beats of, 112 



INDEX. 



237 



Heart, cavities of, 112 

effects of alcohol on, 121 

effects of tobacco on, 122 

form of, 112 

function of, 113 

situation of, 111 

valves of, 116, 117 

ventricles of, 113 
Heart and blood-vessels, 104, 105 

questions on, 127 

synopsis of, 124 
Heart-beats, frequency of, 113 
Heat and work, the result of food 

and oxygen, 150 
Heat, blood, 151 
Heat of skin, 151 

of the body, 148, 151 
in sickness, 152 
regulation of, 152 
regulation of, by the skin, 185, 
188 

questions on, 156 

synopsis of, 155 
Heavy food, 89 

Hemispheres of cerebrum, 166, 222 
Hemorrhage, 121, 222 
Herbivorous animals, 64, 222 
Hinge-joints, 43 
Hip, 17, 18, 222 
Hip-bones, 20, 22, 32 
Humerus, 20, 22, 34, 222 
Humor, aqueous, 203 

vitreous, 203 
Humors of the eye, 203, 222 
Hygiene, 13, 222 

Ice-water, 98, 154 
Images, 205 

Immovable joints, 41, 42 
Important muscles, 55 
Impure air, effects of, 140 



Incisor teeth, 82, 222 
Index-finger, 18, 222 
Indigestible food, 89 
Indigestion, 97 

Injurious habits to digestion, 97 
Insensible perspiration, 187 
Inspiration, 130, 222 
Inspired air, course of, 130 
Instep of foot, 36, 222 
! Intellect, 222 
i Intelligence, 168 
Internal ear, 213 
j Intestines, 80, 90 
attachments of, 90 
coats of, 90 
large, 80, 90 
motions of, 91 
projections from inner surface 

of, 91 
small, 80, 90 
openings into, 92 
! subdivisions of, 90 

work of, 91 
i Intoxication, 223 
Introduction, 13 
questions on, 19 
synopsis of, 18 
I Involuntary muscles, 50, 223 
Involuntary nature of breathing, 

138 
Iris, 203, 223 

Jaundice, 94, 223 
Jaw, lower, 29, 30, 81 

upper, 29, 30, 81 
Joints, 41, 44, 223 

accidents to, 44 

ball-and-socket, 44 

classes of, 41 

gliding, 43 

hinge, 43 



238 



INDEX. 



Joints, immovable, 41, 42 

movable, 41, 42, 43 

pivot, 44 

questions on, 45 

slightly movable, 41, 42 

synopsis of, 45 

varieties of, 43 
Judgment, 168, 223 
Juice, gastric, 87 
function of, 88 

pancreatic, 95 

Kidneys, 223 
Knee-pan, 20, 22, 36 

Lachrymal bone, 29 

duct, 206, 223 

gland, 206, 223 
Lacteals, 96, 124, 223 
Lambdoid suture, 42, 223 
Large intestine, 80, 90 
Larynx, 130, 131, 223 

form of, 130 

parts of, 130 

situation of, 130 
Lashes, 202 

Lead in drinking-water, 71 
Leaf, skeleton of, 160 
Leg, bones of, 20, 22, 36 
Lens of the eye, 203, 223 
Lids, 202 

granular, 208 
Ligaments, 43, 223 

capsular, 43, 44 
Light food, 89 
Light in reading, 207 
Limbs, 18 

lower, 18 

upper, 18 
Liquors, 73 
Little finger, 18, 223 



! Liver, 93 

cells, 94 

drunkard's, 95 

unhealthy, 95 

uses of, 94 

and gall-bladder, canal from, 92 
Living beings, 14 
Lower jaw, 81 
Lungs, 135, 136, 137, 223 

circulation through, 114, 115 

effects of tobacco on, 143 

shape of, 135 

structure, 136 
Lymph, 122, 223 
Lymphatics, 122, 123, 223 

Malar bone, 29, 30, 224 
Malt, 72, 224 
Marrow, 24, 224 

Meals, regularity, time, and quan- 
tity of, 69 
Meat, 67 

Medulla, 165, 167, 224 
Membrane, mucous, 86 

synovial, 43 
Memory, 168 
Metacarpus, 35, 224 
Metatarsus, 20, 22, 36, 224 
Methods of cooking, 69 
Microscope, 106, 224 
Middle ear, 211 
Middle finger, 18, 224 
Milk, 67 

appearance of, under the micro- 
scope, 67 

composition of, 68 

skimmed, 68 

source of, 67 

teeth, 79 
Mind, 168 
Mixed muscles, 50 



INDEX. 



239 



Moisture, effects upon heat, 154 
Molar teeth, 82, 224 
Morphine, 174, 224 

habit, 174 
Motion, nerves of, 171 
Mouth, 79, 80 
Mouth-breathing, 138 
Mucus, 87, 224 
Mucous membrane, 86, 224 
Multiple stomachs in some animals, 

89 
Muscles, 46, 224 

action of, 51 

and exercise, 56 

belly of, 48 

biceps, 53, 54, 55 

care of, 56 

chest, 56 

contraction of, 51 

effect of alcohol on, 57 

effect of tobacco on, 57 

functions of, 47 

groups of, 53 

importance of, 55 

influence of nervous system on 
action of, 52 

number of, 54 

of eye, 204 

paralyzed, 53 

pectoralis, 54, 55 

questions on, 61 

shape of, 54 

size of, 55 

synopsis of, 59 

temporal, 55 

triceps, 53, 55 
Muscle-fibres, 47 
Muscle- tendons, 48 
Muscle-tissue, 47 

involuntary, 50 

kinds of, 49 



Muscle-tissue, mixed, 50 

voluntary, 49 
Muscular movements, complex, 53 
Mute, deaf-, 211 

Nails, 189 

care of, 192 
Narcotics, 173, 225 
Nasal, 225 

bone, 29, 30 

duct, 207 
Near-sightedness, 208, 225 
Neck of tooth, 81 
Nerves, 162, 169, 225 

crania], 167 

kinds of, 171 

of eye, 205 

of hearing, 213 

of motion, 171 

of sensation, 171, 185 

of smell, 196 

optic, 205 

spinal, 169, 170 
Nervous system, 158, 159 

absence of, in plants, 160 

actions of, 162 

divisions of, 161 

effects of alcohol on, 175 

effects of coffee on, 177 

effects of tea on, 177 

effects of tobacco on, 176 

functions of, 161 

most perfect in man, 161 

questions on, 188 

rapidity of action of, 163 

synopsis of, 177 
Nervousness, 173 
Nitrogen, 107,225 
Nose, 195 

bridge of, 196 

function of, 195 



240 



IXDEX. 



Nose, parts of, 196 

questions on, 199 

synopsis of, 198 
Nostrils, 196, 225 

Occipital bone, 27, 29, 225 

Occiput, 225 

Oculist, 225 

(Esophagus, 80, 84, 85, 134, 225 

Oil-tubes, 188 

Old -sight, 209 

Openings into small intestine, 92 

Opium, 173, 174, 225 

habit, 174 
Optic, 225 
Optic nerve, 205 
Orbits, 30, 225 
Organ, 15, 225 
Outer ear, 211 
Oxygen, 107, 225 

Pancreas, 95, 226 

canal from, 93 
Pancreatic juice, 95 

uses of, 96 
Paralysis, 226 
Paralyzed muscles, 53 
Parietal bone, 27, 29, 226 

suture, 42 
Parotid gland, 84, 226 
Passage for air, 134, 135 

for food, 134, 135 
Patella, 20, 22, 36, 226 
Pectoralis muscle, 54, 55, 226 
Pelvis, 22, 30, 32, 226 
Pepsis, 88, 226 
Perfume, 198 
Pericardium, 112, 226 
Periosteum, 24, 86, 226 
Peritoneum, 90, 226 
Permanent teeth, 80 



Perspiration, 154, 187, 226 

insensible, 187 

sensible, 187 

uses of, 188 
Perspiration-tubes, 187 
Phalanges, 20, 22, 35, 36, 226 
Pharynx, 226 
Physiology, 13, 226 
Pivot-joints, 44 

Plants, absence of nervous system 
in, 160 

food of, 64 

life in, 14 

life and growth of, 140 
Plants and animals, difference be- 
tween, 15 

similarity in structure of, 159 
Plasma of the blood, 107, 226 

uses of, 108 
Pleura, 138, 226 
Pores, 187, 226 
Projections on inner surface of 

small intestine, 91 
Proper food, 68 
Protection of windpipe, 132 
Pulmonary artery, 114, 227 
Pulse, 118 

Pulp of tooth, 81, 227 
Pupil of eye, 203, 227 
Purification of the air, 140 

of blood, 115 

of drinking-water, 71 
Pylorus, 80, 85, 90, 227 

Quick eating, 97 

Radius, 20, 22, 34, 227 
Reading, precautions in, 207, 208 
Reason, 168, 227 
Red blood-globules, 106 
use of, 107 



INDEX. 



241 



Reflex action, 151, 227 
Refuse materials, 150 
Reptiles, blood of, 107 
Respiration, 130, 227 
Retina, 203, 205, 227 
Ribs, 33, 227 
Ring finger, 18, 227 
Root of hair, 188 

of tooth, 81 
Rum, 73 
Russian baths, 191 

Sacrum, 31 

Sagittal suture, 42, 227 
Saliva, 83, 227 

uses of, 84 
Salivary glands, 83, 227 
Scalp, 17, 227 
Scapula, 20, 22, 32, 34, 227 
Scarf-skin, 186, 227 
Scents, sweet, 198, 227 
Sclerotic coat of the eye, 202, 22^ 
Sensation, organ of, 185, 227 

nerves of, 171, 185 
Senses, 184/228 
Senses, special, 184, 228 

hearing, 211 
Sense of sight, 201 

of smell, 195 

of taste, 199 

of touch, 184 
Sensible perspiration, 187 
Serum of blood, 109 
Shoes, improper, 25, 26 
Shoulder-blade, 20, 22, 32, 34 
Sight, old, 209 

organ of, 204 

sense of, 201 

questions on, 210 
synopsis of, 210 

weak, 208 

16 



I Skeleton, 20, 22, 228 

care of, 25 

front view of, 20 

of leaf, 160 

parts of, 27 

position of, 21 

questions on, 39 

side view of, 22 

synopsis of, 37 
Skimmed milk, 68 
Skin, 184 

a means of regulating the body- 
heat, 185, 188 

as the organ of sensation, 185 

attachments of, 187 

care of, 189 

color of, 186 

heat of, 155 

necessity for, 184 

questions on, 194 

scarf, 186 

structure of, 186 

synopsis of, 197 

thickness of, 184 

throwing off water, salts, and 
poisonous matters, 185, 188 

true, 186 

uses of, 184 
Skull, 27, 228 

bones of, 29 
Sleep, 172 

amount of, 172 

children's, 172 

uses of, 172 

time for, 172 
Sleeplessness, 173 
Small intestine, 80, 90 
Smell, nerves of, 196 

sense of, 195 
in lower animals, 196 
questions on, 189 



242 



INDEX. 



Smell, sense of, synopsis of, 198 

uses of, 198 
Smelling and breathing channels, 

196 
Smoker's sore-throat, 143 
Sole of foot, 17, 18, 36, 228 
Sound, 213 

Sounds, production of, 133 
Spaces, air, 137 
Speaking, 134 
Special senses, 184, 228 
Spinal, 228 

canal, 31 

column, 30, 31 

cord, 31, 162, 169, 170 

nerves, 169, 170 
Spine, 31, 228 
Spleen, 98, 228 
Squint, 204, 228 
Starch, 64, 65, 228 

digestion of, 96 
Starchy food, 64, 65 

digestion of, 92, 96 
Sternum, 20, 22, 32, 34, 228 
Stimulant, 228 
Stirrup, 212 
Stomach, 80, 85, 228 

discovery of mode of action of, 
89 

effects of alcohol on, 89 

effects of tobacco on, 89 

form of, 85 

multiple in some animals, 89 

structure of, 85, 86 

uses of, 88 
Sublingual gland, 84, 228 
Submaxillary gland, 84, 228 
Sugar, 66 
Sugary food, 66 
Summer, keeping cool in, 153 
Sunstroke, 154 



Suture, coronal, 42, 228 

lambdoid, 42 

parietal, 42 

sagittal, 42 
Sutures, 42, 228 
Sweetbread, 95 
Sweets and sours, 97 
Sweet scents, 198 
Synovial fluid, 43, 228 

membrane, 43 
System, 160, 229 

Tarsus, 20, 22, 36, 229 
Taste, sense of, 199 
abuse of, 200 
questions on, 201 
synopsis of, 201 
Tea, 177 
Tear-duct, 207 
Tear-gland, 206 
Tear-sac, 207 
Tears, 206 
Teeth, 79, 81, 82 

bicuspid, 82 

canine, 82 

care of, 83 

crown of, 81 

fang of, 81 

incisor, 82 

milk, 79 

molar, 82 

names of, 82 

neck of, 81 

parts of, 81 

permanent, 80 

root of, 81 

structure of, 81 

temporary, 79 

uses of, 82 

wisdom, 81 
Temple, 28, 229 



INDEX. 



243 



Temporal bone, 28, 29, 229 

muscle, 55 
Temporary teeth, 79 
Tendon of Achilles, 56 
Tendons, 48, 229 
Thermometer, 151, 229 
Thigh, 17, 18, 229 
Thigh-bone, 20, 22, 35, 36 
Thorax, 18, 20, 22, 33, 229 
Thought, 168 
Throat, 80, 84 
communication with the middle 

ear, 212 
effects of tobacco on, 143 
Thumb, 18, 229 
Tibia, 20, 22, 36, 229 
Tight clothing, effects of, on breath- 
ing, 143 
Tissues, 15, 229 
Tobacco, 229 
effects on circulation, 122 
on digestion, 98 
on heart, 122 
on lungs, 143 
on muscles, 57 
on nervous system, 176 
on skeleton, 27 
on stomach, 89 
on throat, 143 
Tongue, 85, 199 
questions on, 201 
structure of, 199 
synopsis of, 201 
uses of, 199 
Touch, organ of, 185 
sense of, 184 
questions on, 194 
Touch, sense of, synopsis of, 193 
Trachea, 131, 134, 229 
Training, 58, 229 
of brain , 168 



Triceps muscle, 53, 55, 229 
True skin, 186 
Trunk, 18, 229 

bones of, 30 

cavities of, 18 
Tube, bronchial, 136 

Eustachian, 213 
Tubes, oil, 188 

perspiration, 187 
Tubule, 229 

Tubules, gastric, 87, 88 
Turkish baths, 191 

Ulna, 20, 22, 34, 229 

Uncleanliness, results of, 189 

Valve, 229 

Valves of heart, 116, 117 
Valves of veins, 119 
Vegetable food, 64, 229 
Vegetables, green, 64 
Veins, 104, 117, 119, 230 

valves of, 119 
Ventilation, 140, 230 
Ventricles of heart, 112, 230 
Venus' fly-trap, 14 
Vertebra-, 31, 230 

union of, 31 
Vesicles, air, 137 
Vitreous, 230 

humor of eye, 203 
Vocal cords, 132, 230 
Voice, production of, 134 

organ of, questions on, 146 
synopsis of, 144 
Voluntary muscles, 49, 230 

Wakefulness, 173 
Warm-blooded animals, 151 
Warmth in winter, 153 
Water, 66 



244 



INDEX. 



Water, ice-, 154 

drinking-, 69 

of rivers, 71 
Wax of ear, 211, 215 
Weak-sight, 208 
Whiskey, 73 

White blood-globules, 106 
White of eye, 202 
Will, 168 
Wines, 73 
Windpipe, 131, 134, 230 

branches of, 131, 135 



Windpipe, form of, 134 

protection of, 132 

rings of, 131, 135 

situation of, 134 
Winter, keeping warm in, 153 
Woollen clothing, 152 
Work and heat the results of food 

and oxygen, 150 
Wrist, 20, 22, 35 

Yeast, 67, 230 



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